Steven, Thomas, and I began our first threesome as boyfriend-boyfriend-girlfriend, nicely cementing our new relationship.

By habit, we always started with masturbation. They then placed their penises together and Thomas gripped both of them, stroking them up and down. They kissed with tongues, and I took the chance to run my hands gently over both their bodies: from their chests, down their arms and legs, then back up again.

Steven broke the kiss and grabbed Thomas's arm. 'Slow down, it's too good.'

Thomas complied. The boys moved back a little and let me press my breasts against them. They ran their hands over me and both worked their way to my nipples.

I'd broken the news that I'd changed my contraception and they were free to finish inside me. It was decided Thomas would go inside me first as he usually took longer than Steven. It must have felt better than usual because he was much quicker than expected. Instead of about thirty minutes, he spurted in less than half that time, all the time Steven was stroking and kissing him. I could feel his liquid going deep inside me, and it dribbled out a little when he withdrew.

When Steven took his turn, he commented how nice it was to feel our mutual boyfriend's sperm while thrusting into me. Thomas quickly wiped himself up and started touching us both as we had sex in front of him. Within a couple of minutes, Steven had added his load to what was already there. I didn't manage to orgasm from either of their thrusts, but I still enjoyed the experience.

We all wiped up with our towels, then I took them to the washing machine in the kitchen. We'd had a little drink before the threesome, and I spotted one of the glasses on its side, spilling wine onto the floor. I didn't remember hearing it fall, but we were in a hurry to head to the bedroom, so I stood it up and threw one of the towels over the spillage.

The boys and I squeezed into my bed for the night because they had to be up for the early train, heading home for Christmas. Our meet-ups over the term had cost a fortune in travel fares, but we all felt it was worth it.

After waving them off at the station the next day, I returned to the flat, and made a start on sorting out what food would and wouldn't keep until my return in January. To my surprise, one of my flatmates walked in.

'Fiona? You... What are you doing back?'

'I just nipped out to Asda.'

'I mean... Didn't you...? Are you not going home for Christmas?'

'No,' she said, seeming confused. 'I don't get on with my folks. You haven't left either.'

'No, I'm going home in a day or two. I...' Deciding to dampen it down, I said,  'I've had a couple of friends over.'

'Last night? Yes, I heard you. Sorry for knocking your wine over. I was... I was just in a hurry to get out. I'll get you a new bottle.'

There was a silence, an awkward one. We both knew the score.

'You heard us, though?' I said.

'Look, it's fine. We all have guys over. It happens. I just... just thought I'd get out and leave you for a bit. I mean, you clearly thought everyone was away, so...'

'So...'

'It's fine, really.'

I thought for a minute. Of all my flatmates, I probably knew the least about Fiona because she was so quiet. Maybe we could talk now. 'Do you want some wine? I've got more in the fridge, four bottles. I didn't know what the boys would like.'

'I'll have one.'

We started drinking. I asked Fiona what had happened with her parents, but she didn't want to talk about that. She was far more interested in what happened the previous night.

I explained to her that Steven and Thomas were both my boyfriends and I was their girlfriend. But after I said that, I then had to fill in the back story for context, namely that Jack and Steven had been a couple. In fact, for every piece of back story, I had to give details from even earlier to give context about what I'd just said.

By the time we opened the second bottle, I'd worked all the way back to our changing room masturbation at sixteen. Fiona listened intently, increasingly fascinated by each detail as it arose, and asking questions about our relationships and the dynamics in the group.

I was excited to be able to talk to someone outside the group about what we did, not to mention tipsy, so I didn't mean to ask what I asked:

'Do you want to sleep with one of them?'

There had long been an unspoken agreement in the group that we could masturbate and/or have sex with any other member. But that agreement didn't extend to any outsiders.

'Um...' she started.

I hoped she'd say no, but the more she thought about it, the more the idea appealed to her – she ended up giving me an enthusiastic yes.

I left it until the next day before telling the rest of the group, after a restless night thinking about how they would react. I shouldn't have worried. Steven and Thomas were up for it without any persuasion. Tiff and Samantha wanted to know everything about her: height, hair colour, cup size, and so on. I'd offered to stay with Fiona over Christmas, but she said she enjoyed the peace and quiet, so I went as planned but took as short a break as possible.

Early in the New Year, I brought my boyfriends back with me to meet Fiona. None of the other flatmates had yet returned, but we sat in my bedroom where it was more comfortable. I introduced them properly over pizza and drinks and let them get to know her. They'd already spoken by phone and video chat, but that hadn't been the same.

We'd proposed during these calls that she should sleep with whichever boy she had better rapport with, or not at all if they didn't click. So far, it looked like Thomas was the better match; they were both quite shy and they'd bonded over that.

Because our group members were accustomed to seeing each other naked, the boys and I slowly laid out our towels and began to strip and kiss without thinking, but Fiona was hesitant.

Like me, she wasn't attracted to women. However, we'd become more open to talking about sex and orgasms, and she mentioned she didn't like to wear a bra indoors. We agreed if it was just us in the flat, we both could go topless, but any nakedness or masturbation would be in private, except when the boys were present.

'I just...' she said, 'I've never let anyone watch me before. I don't even do it all that often.'

'That was the first rule we laid down at school,' said Steven, 'everyone was sworn to secrecy within the group and we weren't allowed to laugh at each other.'

'Yeah, I know, it's just new to me.'

'If you don't like it, you don't have to stay. Nobody's going to force you to do anything.'

She hesitated again, then crossed her arms and removed her top. 'I'll give it a try.' She unclipped her bra, then took off the rest of her clothes to match our level of nakedness.

I've watched a lot of female friends masturbate. They all touched their nipples to one extent or another, but that was the only similarity. Some played only with their clits while others placed fingers or objects inside; some had to stop completely between orgasms and others carried on stroking; some screamed and others were quiet. The list went on.

But Fiona had a technique I hadn't seen before: she slowly lay on her front on the bed, head turned to one side. She carefully wedged a hand between the covers and her body to stroke herself. It didn't take long for her to find the sweet spot on her clit and start thrusting herself onto the palm of her hand in time with her strokes. The boys had settled into their rhythms and were probably about to start touching each other.

Meanwhile, I'd been working on my ejaculation technique; not only could I reliably shoot every time but I was now able to catch most of it in an empty cup. When I felt my first orgasm happen, I filled it with about a finger-width of fluid. I handed it to Steven for a sip; he gave it to Thomas, who did the same. They kissed, then he held it out to my flatmate.

'Oh,' said Fiona. 'You really do squirt.'

'Just like I said.'

'Oh, I didn't realise it was so much. I thought you just meant a little dribble.'

'It's buckets,' said Thomas. 'Have some if you want.'

'Um... I... no, thanks.'

I took back the cup and drank the liquid, kissing each of the boys on the mouth. I addressed Fiona as we kept ourselves aroused. 'Once you have your first orgasm, we can start.'

'It's fine, we can start just now. It might be a while before I get off. I've never done it in front of anyone.'

'I know how you feel,' said Thomas. 'It takes me a while sometimes. Is there anything we can do to help you?'

'Well,' she said, suddenly blushing, 'no, it's nothing.'

'Go on,' said Steven, 'if there's anything we can do, we'll do it.'

'Well,' she said, still blushing, 'okay, it's a bit weird.'

Steven laughed. 'This whole group's weird. Most of us are only friends because we love to wank.'

'Could you, and you don't have to, could you and him kiss again? Only if you want to.'

'Can I kiss him? That's so cute. Of course I can, it's one of my favourite things.'

The boyfriends leaned in to kiss theatrically with tongues. They were still stroking their own penises so they swapped to pleasure each other. Meanwhile, Fiona watched them like a hawk, her strokes and palm thrusts becoming more and more urgent. At orgasm, she let out a repeated 'Coo' sound; again, something I hadn't heard from any other woman.

The boys broke their kiss and we paired off. By this point, it was clear that she had more of a connection with Thomas, so he went with her, while Steven joined me and I immediately went down on him, trying not to get him off too quickly.

I was still able to see Thomas and Fiona from where I was. They took longer to start, beginning with a tentative kiss. She was still on her front, but moved a little to let him touch one of her boobs, then she let his hands slip down her body.

Through a lot of experience, I knew when Steven was building up to orgasm, so I withdrew my mouth before he finished and lay on my back, opening my vagina a little for him. He didn't wait, entering me straight away. There was a spot inside me that I had to stimulate before I could ejaculate. It was pleasurable enough when he hit it, but a penis couldn't provide the upward pressure that a finger can.

Meanwhile, Thomas and Fiona were still kissing as he fumbled with the condom. Still inside me, Steven reached over and helped him pull it over his penis, then kissed him on the neck before turning his attention back to me.

I kept watching them: Fiona told him she wanted him to enter from behind, adding that she always had sex that way. She lay flat on the bed and wedged her hand underneath her, just like when she was masturbating. Thomas struggled to get in just the right position. When he found his mark, though, he went for it.

Steven didn't take long to ejaculate inside me. A little semen dripped out, so I licked it up. I could never persuade him to taste his own but he happily swallowed it when Thomas would spurt.

There was no danger of Thomas finishing any time soon with Fiona, but I could see the pleasure on her face as she touched her clit at the same time.

'Can we come over and help?' I asked.

They both nodded. I sat next to Thomas and sensually kissed his neck, letting my boobs rub against him. Steven worked his way to Fiona's boobs and touched her nipples in the way I like it, which seemed to work for her as well.

When Thomas eventually orgasmed and withdrew, Fiona was a happy sweaty mess. She turned on her back, sat up, and wouldn't stop kissing him. Although he wasn’t her boyfriend, they seemed made for each other so I let them enjoy their moment.

Cleaning up, we talked about how much we enjoyed the space to have our little orgy, and how we all wanted to do it again before long. There seemed an obvious answer that none of us had considered before: Fiona and I should move into our own place together.