Katie was waiting at home for him to arrive. He was her Dom, Master Rob, the guy who gave the orders, and she obeyed, or else. She knew what 'or else' would be like since she had ventured into disobedience once before. So her Master had tied her naked to a chair, kneeling on the seat and hunched over the back, helpless, as he spanked her with a riding crop until she was red and sore on her rear, inner thighs, and her pussy. It had moments of arousal, but in the end, it was quite painful. While she enjoyed a hand spanking over his knee anytime, that was discipline for her disobedience, and she didn't want it again, so she always tried hard to obey, if she could.

But lately, her Master had been telling her that he wanted to fuck her in the ass, and while she was excited, she was also a bit afraid of anal. He gave her a set of butt plugs to wear to get her ready, and she found it difficult to obey all he asked her to do. She was to wear one every day, and send a photo to him showing the butt plug in her, once in the morning, once mid-afternoon, and once at bedtime before she wore it all night. Despite her concerns, she obeyed and did as he told her. She had been wearing them every day, all day, and sending him photos as he required. He told her to increase the size every two or three days, until she was now wearing the largest one for the last three days. It looked pretty in her rear, its blue gems gleaming when she looked at it in the mirror, but that was a misleading view considering the pain involved in putting the plugs in and removing them. But she did it, and she was ready.

So, today was to be the day she would have her first anal. She was excited but also still a bit scared, since she knew her Dom was well-endowed, and she figured he would want to put his entire penis in her. But she waited as she always did near the front door when he was to arrive. She was naked and on her knees, sitting up straight. Anything else would bring the 'or else' clause into play. He had a key to her apartment, so when she heard the key opening the door, it would signal the loss of her freedom until he left, usually in the morning; he would tell her what to do the whole time he was there.

She waited, and then she heard the key in the door. Then Master Rob entered, saw her kneeling at attention, and smiled.

"I'm pleased to find you waiting as you were instructed. Are you wearing the big plug?" Master Rob asked.

"Yes, Sir, I am," submissive Katie replied.

"Let me see," he said.

Katie turned so her rear was toward him and leaned over until her head was on the carpet, raising her ass in the air. Master Rob looked at her and gave her a friendly swat on her cheek. Then he grabbed the butt plug and pulled on it, turned and twisted it in Katie's ass so that she could feel it moving. It made her squirm, and despite a little pain, it was quite arousing, but she kept quiet as she knew she was supposed to.

"Well done, my slut! You have pleased me," he stated.

Katie resumed her kneeling position.

"Would Sir allow me to give him a blow job?" she asked.

"Not now. Maybe later. First, I'll take a shower while you play with yourself here on the floor," he stated.

With that, he walked to her bedroom and went to her bedside drawer. He returned with a dildo and a vibrator.

"Kneel and spread your legs, and use these to arouse yourself, " he said. Then he gave her the toys.

"When I come back from my shower, you'd better be using them, slut. I want you turned on and wet, but you are not to cum. You must hold that for later," he commanded.

"Yes, Sir, " Katie replied.

And Master Rob left for the bathroom to shower.

o o o

Katie resumed the kneeling position but with her legs spread apart, as ordered, and started using the vibrator to arouse herself. She ran it up and down her labia and forced her pussy lips open, then ran it up and down her slit. It felt good, and she was getting wetter than she already was. Using her free hand, she inserted the dildo into her pussy and pushed it deep into her; it enhanced the arousal she felt from the buzzing on her slit. She tried to take it easy by avoiding her clit so she wouldn't need to cum, but it was hard. She got very aroused and very wet, and began to squirm, being so turned on.

As strong as her arousal was, she knew she had better dial it back, or she would cum, so she pulled the vibrator away and continued with just the dildo. This helped her maintain a state of arousal that she could withstand, and she would use the vibrator again when she heard her master come out of the bathroom.

After about half an hour, she heard Master Rob returning, so Katie resumed using the vibrator.

"Okay, you can stop now, and crawl to the bedroom, slut," he said.

"Yes, sir," Katie replied.

o o o

She put the vibrator down and pulled the dildo from her sopping wet pussy. Master Rob took them as Katie got on all fours and crawled down the hallway to the bedroom. Once there, he had Katie climb on the bed, still on all fours and over a towel that he had placed there, and Master Rob started to play with the butt plug, pulling it partway out and putting it back in, and wiggling it about to arouse her. As Katie squirmed in a little pain and a lot of arousal, he began to finger her pussy, rubbing her up and down and paying special attention to her clit. He circled it and swirled around it, making her swollen nub drive her wild.

"Okay, now on your back, naughty slut," he ordered, and submissive Katie obeyed.

Once Katie was on her back, Master Rob undressed and climbed onto the bed, opened her legs, knelt, then leaned down and began to lick her snatch. He licked her pussy up and down with his tongue, being sure to swirl about her clit frequently, which drove Katie crazy. She bucked and squirmed as he ate her out, and then he reached for her breasts and assailed her nipples, rolling, pinching, and pulling on them while he continued to eat her pussy with gusto. This continued for over half an hour, and Katie had to bite her lip and writhe in pleasure many times, trying to delay cumming for as long as she could. But partway through, the pleasure overwhelmed her and she came intensely, bucking and moaning loudly as Master Rob would not stop.

When he finally did, he had Katie pull her legs up, spread them, and hold them there with her hands on her knees, leaving her completely exposed. Then he pulled the butt plug from Katie's ass, which gave her a jolt of arousing relief, but he soon replaced it with a miniature baseball bat about twelve inches long. He pushed it about halfway into her asshole and began to swirl it, rubbing the insides of Katie's colon. It was a strange feeling for her, but not unpleasant, and she squirmed about in response. After a few minutes of wiggling it inside her, he removed it, but stuck two fingers into her rear instead, and then added a third. He rammed them in and out with some force to open Katie's hole even more, and she moaned in mild pain and increasing pleasure.

"Please, sir, I'm so ready for your cock," she pleaded.

"All in good time, my sweet slut!" he cautioned.

Master Rob continued expanding her asshole with his fingers for another minute. Next, he removed his hand and squeezed out a good amount of lube and applied it to her asshole and rim, before adding some to his erect penis, which had been waiting at attention all this while. Master Rob had Katie get back on all fours and positioned himself behind her.

Katie tried to loosen her muscles to relax her hole as Master Rob pressed his cock against her opening. It was still pretty tight despite the lube, but looser after the finger stretches and Katie's relaxation. He eased into her, slowly pushing the head of his penis all the way in. It felt huge to Katie, like the head of the butt plug, but it did not pop in and let her opening close around it; it stayed big. She gasped a bit, and her breathing became more labored as she coped with the size. He pushed further in, then backed off before pushing forward again. Katie was feeling the full girth of her Master's penis as he pushed it further into her with each thrust.

"You have such a tight asshole, dear slut Katie... and I love it!" Master Rob exclaimed.

"Thank you, sir," Katie managed to gasp.

Master Rob held Katie's hips to brace her and slowly picked up speed, cycling in and out of Katie's ass, while she clenched her teeth and breathed in gasps. Soon, Katie got used to the fullness of his cock in her rear and relaxed enough to enjoy the ass fucking she was getting. As it began to feel good, she started to push back against his thrusts and was soon grinding back into him. He pushed the pace and began fucking her ass with gusto, and she was pushing back in sync while she enjoyed the fullness and was very aroused by it. Master Rob fucked Katie's ass for another ten minutes before he jerked, spasmed, and exploded his ejaculate into her. He jerked several more times as he filled her with his hot semen. She felt the warmth flow through her and had some sort of orgasmic reaction that felt wonderful.

o o o

After Master Rob had come and Katie had orgasmed, he pulled out, and his semen flowed from Katie's ass down her leg and onto the towel below them. He massaged her rear as he spoke.

"So, how was it, my sexy Katie?"

"It was hard at first, sir, and it hurt a little, but then it felt good. I think I'd like to do it again soon, if we could," Katie replied.

"That can be arranged, my lovely slut. I'll add it to our sexual repertoire and take you in the ass whenever I feel like it," he stated.

"Thank you, sir!" she exclaimed with happiness in knowing that she had pleased her Master.

And then they both cleaned up and got dressed. Katie was happy that she had gotten through the test and actually enjoyed it. And she could tell her Master did as well. She knew he would take her in the ass whenever he wanted, and that it would be a nice addition to the many ways he pleased her sexually; she could look forward to many anal orgasms ahead!