I don’t think I had any masturbatory fantasies about anyone else for weeks. I relived the bathroom fantasy that I had a couple of months ago almost daily. Ever since I heard my friend Gary’s 20-year-old daughter, Kate, whom I had known all my life, upstairs at their house in the shower, I could think of little else.

I had been able to hold out from climaxing a little further into my fantasy each time I daydreamed about her. I had managed to prolong the scenario of our imaginary interaction beyond the initial thrill of her asking to smell my cock when I saw her soiled toilet a little further; each time I would masturbate thinking about it.

I imagined that sometimes I would finger her while she sat on the sink. Sometimes I would eat her ass while she bent over it. Sometimes I would fuck her face while she sat on the toilet, and sometimes we would climb into the shower with almost scalding hot water pouring over us while I spanked and beat her ass red.

I don’t know where the aggression was coming from in my head; maybe I was taking out seven years in the wilderness on her since my marriage had ended, when I should have been taking it out on myself. I also couldn’t figure out why I had predisposed her with a submissive personality when I had never had a hint of this from the little I had seen.

All of this, of course, made things very awkward (for me) whenever I saw her from this point on. It was uncomfortable to even look her in the eye, to be honest. I hoped she couldn’t sense any change in me.

I was over at their place one Saturday afternoon when she came in from work late in the day. She had a part-time waitressing job while she studied psychology at university. She had dyed her strawberry blonde hair platinum blonde since I last saw her. It took me back a bit. I’d never had any preference for a particular hair colour, but the white blonde sexualised her more than normal, and she was wearing a black silk-looking blouse with a black knee-length work skirt with black tights.

Her breasts, which I had now estimated to be around a 34B, jiggled under the fabric of her blouse. I don’t think I had ever seen her in tights before or thought about her in them either, actually. It was a thrill to know that I was going to be going home with material for a new fantasy.

She flopped down on the sofa across the room from me.

“Hi Jamie,” she said.

“Hey, how was work?” I replied.

Pleasantries continued, and she kicked her shoes off, letting me take in her stocking feet.

“Are you out tonight?” I asked her.

“Yeah, there is a party at Nicki’s place. Sam is meeting me there later. Will probably stay over.”

Sam was her boyfriend, who I saw from time to time whenever he was over at Kate’s family’s place. Nicki was Sam’s sister.

“The new hair looks nice,” I complimented.

“Thanks, J!” she said. “Fancied a change. Hey, take a look at the new car I’m getting next week,” she said as she got her phone out. She climbed off the sofa and came over to the armchair where I was sitting, perched on the arm.

She scrolled through a few pictures of a second-hand Clio she was getting in the week while she held the phone in front of me. I nodded and smiled and told her it looked great and asked her about the spec while just staring at the phone, wondering what other pictures she had got on there.

Was she one of those young girls who loved taking full-length selfies in her underwear? Did she have any pictures of herself on there standing naked, in her bathroom, assessing the size of her non-existent love handles, getting upset with herself that her breasts were too small? (They weren’t).

My mind started trying to concoct a scenario where I could be left alone with it, unlocked, for a few minutes. I had an unrelenting appetite for new content of hers, video, photos, anything I could get my hands on to fulfil my increased desire for new fantasy.

I had browsed her social media and seen many selfies and lip-sync videos she had posted, giving me a different insight into her personality as she had gotten older. They made me feel my age.

She placed her hand on my shoulder as she got up from the arm of the chair.

“You staying for dinner?” she asked.

“Sure.”

“Cool, I’m going to get changed and eat here before going out to Nicki’s.”

She headed off upstairs. I watched her go. Looking at her ass and still trying to create a picture in my head of its true shape. The skirt she wore was pretty straight and not very shapely. I waited to see what she came back down in.

I heard the shower upstairs turn on after a couple of minutes. ‘Not again,’ I thought.

She reappeared with wet hair and in her dressing gown to eat dinner with us. She was fresh-faced without make-up and looked incredible. She had clearly interrupted getting ready for the evening to eat and was going to finish afterwards. She sat opposite me in her dressing gown, munching on the pizza her mother had cooked for us.

My mind wandered to what might be underneath that dressing gown. I suspected ‘nothing’ as she was in the middle of getting ready. She showed no self-consciousness around me as I had grown up with her. I dropped a napkin on the floor so I had an excuse to bend down and look under the table quickly, nothing to see, sadly except her bright red, newly painted toenails.

I dreamt of the freshly washed folds between her legs. What did she look like down there? I wanted to run my hands up her thighs and squeeze her flesh between my fingers, slowly opening her robe while looking her directly in the eye.

She finished her food, got up to finish getting ready, and left about 8 pm, but was covered up in her jacket before I saw her again to say goodbye for the night.

I retired back to the living room with her family: Mum, Dad, and two younger brothers. David was twelve, and Peter was fourteen. I’d had a couple of beers at this point, only light ones as I was driving home, but I had been there since 4pm, so I needed to piss.

“Oh, you need to run upstairs and use the bathroom up there. We have a leak in the downstairs toilet," Ellie, Kate’s mum, told me.

“No problem,” I said and got up from my seat.

I left the room to walk up the stairs, and my mind started racing. I didn’t get to come up here very often as there was normally no need to, but this was going to be a potential opportunity to be close to Kate’s room. Could I get inside for a moment? Could I retrieve a new treasure to propel my growing fixation?

I was nervous about what they could hear downstairs, but the TV was on, and hopefully, I could buy a couple of minutes, although I did need to piss too.

I gingerly turned to the direction of her room first. The door was closed, but I managed to open it without a sound. Even though the floorboards and carpet were pretty silent, in my head, it sounded like I was walking on a carpet of potato chips.

I walked in the open door gingerly and was standing in her room. My stomach was in my mouth. I got my phone out of my pocket. I took a couple of quick snaps of the room. I didn’t immediately see anything out of the ordinary. It looked pretty much like what I imagined a 20-year-old woman’s room to look like.

A couple of pictures on the walls, printed-out photos of Sam on her dresser mirror, a single bed roughly made, with a white and blue duvet and two pink pillows, a couple of stuffed animals on the bottom of the bed, a smart speaker on the windowsill, and an open wardrobe to the left of me. I could see some of her clothes hanging in there and some boxes on the floor.

There were drawers in the dresser, so I gambled on that first, given I only had a few seconds before I was going to have to move to the bathroom. I pulled open the top drawer gingerly. I was presented with her underwear drawer. My cock was rock hard. I was so panicked I was going to get caught. My hands were shaking as I took another picture. I grabbed a pair from the bottom of the drawer and stuffed them into my pocket.

I closed up the drawer, left the room, and closed the door as quietly as I could before tiptoeing across the hall to the bathroom. I locked the door behind me and let out a deep breath.

I pulled open the buttons on my jeans to take a piss. I needed more freedom for my stiff cock than just pulling it out of my fly. I used one hand to force my cock downwards into the toilet as I stood over it to piss.

I let out a deep breath now I was in the safety of a locked bathroom. My heart was still pounding.

I reached into my jeans pocket that were hanging open just below my hips and brought out the pair of panties that I hadn’t properly looked at yet. They were a tiny G-string. Black. Lace see-through section at the front. Single string for the back. My cock jerked up again, and I splashed piss over the back of the toilet. “Fuck” I muttered under my breath. They looked tiny, but said size M on the label as I studied them.

I finished my piss and started tugging my cock with force. I had to soothe my erection, it was so painful. I wrapped Kate’s black G-string around my dick and jerked for dear life. I steadied myself with a hand on the wall in front of me over the toilet.

I pondered how turned on I was getting by this girl, who for the last 20 years had only been a poor excuse for a surrogate stepdaughter at best! How her significance to me had gone through such a metamorphosis as she had become a young adult.

The cotton and lace felt wonderful around my solid cock. I tried to picture her wearing them, the tiny string at the back disappearing between her tight, plump cheeks, continually sliding across her little, locked anal opening.

I took in my immediate surroundings and saw the wicker basket sitting next to the bath under the window.

My heart started pounding in my chest again. Was this dirty underwear? I knew her parents had their own en-suite, so it was only the kids that used this room. I lifted the lid on it, and a pair of black tights and red cotton panties sat on top of the pile of clothing inside.

“Fucking hell,” I said under my breath as I reached for and pulled the panties out of the basket with one hand as I jerked my dick with the other. I inspected the panties and immediately saw two small, thin, dark streaks inside like they had been made by the casual, lazy swipe of an artist’s paintbrush.

I lifted them to my face and held them over my nose. I took a deep breath, imagined her on her knees with her bare ass spread in front of me.

I took another heavy sniff of her soiled knickers and revelled in the deep, musky, sweaty smell. I dreamt of the stale scent of her asshole. I imagined kneading and spreading her cheeks hard as I prepared to sodomise her for the first time, while I tugged my rigid meat in my fist.

A third deep inhalation, I closed my eyes and cried out "Oh god" as I came and threw four thick ropes of semen across the bathroom floor.

“Oh, fuck, oh, fuck”, I whispered breathlessly.

I fell to my knees, out of breath. I could hear footsteps coming up the stairs outside the door.

Some cum hung from my throbbing cock head.

I de-tangled the G-string around my dick and stuffed it back in my pocket. Fuck, how was I going to return these? It had only just dawned on me.

I climbed back to my feet, carelessly wiped my dick off with her red panties, snapped a shot with my phone as a souvenir, tossed them back in the laundry basket, and pulled up my jeans. As much as I longed to take them, I knew they would be missed from the top of the pile. Hopefully, the memory of the G-string I had grabbed from the bottom of her underwear drawer would be easier to overlook.

I flushed the toilet and straightened myself out before exiting the bathroom as Kate’s two brothers, who had come upstairs, were wandering about in their bedrooms with the doors open. I glanced at them and wondered if they had heard me cry out as I came, dreaming about their sister’s hot little rectum.

I returned to the living room and spent the rest of the night chatting with her parents while the TV played an old concert film from the 70’s in the background.

Ellie had gone to bed around 10.30pm and I hadn’t seen the brothers again. It was now 11.45pm and I decided to make the drive home as I was impatiently dying to jerk off again and take my time about it. I said my goodbyes to Gary, as he retired to bed and locked the front door behind me as I walked to my car across the street.

As I was about to open my car door, I heard another car come round the corner, and I looked up to see it was Kate. Did I duck into the car and get out of there with shame hanging over me, or did I wait to say hello? I thought she was staying the night and drinking, so I was confused that she had arrived back.

I decided to stand my ground and waved to her as she pulled in. She climbed out and walked over to me. She was upset.

“Hi, my girl,” I called, eyeing up her red lipstick that had clearly just been recently re-applied.

She came up to me and put her arm around me. There was more physical contact now than there had been in the past as she matured. I froze. I was already stiffening before she arrived, just at the thought of going home with a pair of her knickers to play with for the next few weeks.

“I thought you were gone for the night? Party no fun?” I asked.

“Not really. Sam was horribly drunk and acting like a dick, even as I got there.”

“Oh no.”

“Yeah, drinking games aren’t really my thing,” she sighed.

“Oh dear. Could you not hang out with your friends there?”

“I don’t really have any friends there except Sam,” she replied confusingly.

“Should take me next time,” I said, only half joking, as the thought of a bunch of other 19-to 21-year-olds getting drunk in a house while their parents were away was not a concept I totally hated the thought of. She looked at me directly in the eye while she held my arm in hers.

“I’m not letting my friends loose around you,” she laughed.

“Yeah, I’m sure they would love an old crusty turning up to keep an eye on things,” I said.

“You aren’t old.”

There was a pause, and as I wished she meant that.

“We should go to bed,” she said, breaking the silence. And then laughed and corrected herself. “I should go to bed.”

We were leaning back against the car while she had her arm hooked through mine. She unhooked, and we both leaned forward and straightened up as she moved across in front of me to head back to her house.

The top of her hip brushed against my straining erection as she did, and I froze. “Oh fuck,” I thought, although it didn’t seem to faze her or stop her in her tracks. She had her jacket on, which was quite padded, so maybe she didn’t notice.

She turned around as she reached her drive and looked back at me. She smiled. She looked so fucking sexy as I wished I’d taken the dirty pair of her knickers instead of a clean pair.

“You should buy me dinner sometime now I’m grown up,” she called to me. And I swore she took a distracted glance down at my crotch or in that direction as she turned away. “Text me.”

“I will,” I replied. “That will be fun.”

I glanced down to see how obvious my pant tent was and noticed a corner of lace from her stolen panties hanging out from my left jeans pocket.

I drove home in a state of confusion, panic, and arousal. What had she seen? What had she felt? Did she care? I would find out.