In our second year of college, Fiona and I decided to move out of shared halls and into our own place. We found part-time jobs – which happened to be at the same bar – because the new flat cost more than what we were paying before, but at least we were now the only occupants. After moving in, we held a housewarming, inviting the rest of our masturbation group.

We were looking forward to it so much that we both held off orgasming for three days beforehand. This was easier for her, but I was accustomed to getting off every day or two, so I really struggled not to touch myself.

The first members to arrive were Steven and Thomas. They went to colleges some distance away, so it was always a treat to see them in person. In a recent development, Fiona and I were in a relationship with both boys at the same time, and they were also boyfriends with each other. This meant we could have group sex in many combinations, although she more often paired off with Thomas while I went with Steven.

There was no lesbian contact in the foursome because neither of us ladies were into the same sex. We were, however, fine with any non-contact activities. To save money, we'd rented a one-bedroom place, and it was no big deal to be naked together or to masturbate underneath the covers in our separate beds. When we had a threesome, both of us focussed on the guy without touching each other.

Members had come and gone over the years, but at that point, there were a total of six people in the core group: our foursome, plus Tiff and Samantha. Unlike my flatmate and me, they were very much in a relationship, and we'd see plenty of girl-on-girl action between them.

By habit, our sessions always started off by touching ourselves and watching each other. As we spoke, we heard a background hum of four vibrators, one per vagina, but the boys stuck to using their hands.

'Well,' said Thomas, 'we wanted to wait until we were all together before telling you. Steven and I have just got our own place as well. We're picking up the keys on Tuesday.'

'Oh brilliant,' I said.

'It's about halfway between our colleges,' added Steven, 'and it's nice and quiet so we can have,' he raised his voice, 'a lot of loud gay sex.'

'Steven!'

'What? It's true.'

They kissed, which never fails to turn me on. I pushed my vibrator more firmly onto me. 'That's great. Trust me, you'll never go back to sharing with strangers.'

'Aw, that's lovely,' said Tiff. 'Well, we've got news as well. So last week, I proposed to Samantha and she said yes and so... we're getting mar-ried!'

'That's amazing,' said Fiona. 'Let's see your ring.'

'That's the other bit. We don't actually have them yet because we're not getting finger rings, we're getting clit rings instead.'

'What?' asked Thomas. 'Through your actual... you know?'

'No, dummy. Just the hood.' She moved her toy away to demonstrate. 'Just here.'

'That sounds amazing.'

I thought it sounded really tacky, but I offered my congratulations.

'Kath and Michael are engaged too,' added Thomas. 'She told me.'

'What?' said Tiff. 'But they're cousins.'

'From your school group?' asked Fiona.

'Yes.'

'Well... if they're happy, I suppose...'

'But is it really right?' said Tiff. 'I mean, they could literally be with anyone who isn't a relative.'

The cousin debate went on for a minute, but dropped off as Samantha began to moan. Just after she orgasmed, I felt mine building up and I squirted loads of fluid into my hand. Once Tiff and Fiona had their first orgasms, it was only a matter of time before the mutual touching began.

I could normally predict what would happen here, but this session surprised me.

For a start, I didn't expect Tiff to reach out to Thomas and offer to take over his stroking, which he accepted. Samantha didn't seem bothered by this at all, instead, inserting a finger inside Tiff and gently pushed it in and out.

I was also taken aback by Fiona. She reached for Steven instead of Thomas, and she also wasn't usually one to initiate contact. She leaned over and enthusiastically started to kiss him with tongues as she ran her hands all over his body and he continued to stroke himself.

It didn't take long before Samantha brought out a strap-on. I'd only ever seen her wear it, but she instead fastened it onto Tiff, who held onto it like it was her own penis. Samantha then found a space in the tiny flat to go down on her hands and knees, pointing her back towards her fiancée.

Unsure what to do, I gently ran my hand down Steven's stomach, where he let me take over the stroking and I matched the pace of Tiff as she stroked Thomas. The boys held hands and kissed briefly, prompting me to move my free hand back to my clit.

Without missing a beat on Thomas, Tiff rested the very tip of her strap-on against Samantha's entrance but didn't quite penetrate her. 'Please,' she said, 'I want you inside me.' And then, out of nowhere, Tiff spanked her with her other hand. It was loud enough to make the rest of us stop what we were doing.

The spanked woman looked up. 'Oh, you've never seen us do this before, have you? It's just something that... happens now, I suppose. Nothing to worry about.'

'All right, then.'

We carried on as the sounds of begging and spanking continued. It took a few more minutes until Tiff finally sank the full length of her strap-on inside Samantha, causing her to sigh. I desperately wanted something inside me as I continued to stroke Steven, while Fiona kept on kissing him deeply and touching him everywhere.

Across the room, Tiff had positioned herself so she could still spank and thrust into Samantha while giving oral to Thomas. He normally took ages to shoot his spunk, but from his face, it looked like he was about to burst at any moment.

At my suggestion, I moved to the bedroom with Fiona and Steven, where she pushed Steven roughly backwards onto her bed – again, a roughness I didn't associate with her – and she went down on him. Maybe the three days of not masturbating had something to do with it. I joined her, but we made sure our hands and lips didn't touch.

I'd had discussions with Fiona and the boys about our sexual health; not a nice topic, but a necessary one. We'd been tested and were all clean, and I had a contraceptive implant, but she hadn't yet found a method that worked without side effects. That meant the only time we needed condoms within the four of us was vaginal sex with Fiona. The boys could even have bareback anal as long as they were careful about hygiene.

We were also allowed to have sex with people from outside the foursome, including Tiff, as long as it involved protection. However, we'd talked with her about the boys finishing inside her as well.

Fiona had condoms ready. She reached over to her bedside table, opened one, and rolled it onto Steven while I held down his foreskin. She always masturbated on her front, trapping her hand between the bed and her stomach, and liked to have sex the same way.

When she held open her vagina, I guided him inside. She started to stroke her clit rhythmically as he thrust in and out. I then started touching him all over. He was normally quick to shoot, but he must have been holding off because she orgasmed twice before she asked about him finishing inside me instead. He agreed eagerly.

I like all different positions, but it seemed easiest to copy my flatmate. Steven withdrew from her, swiftly removed his condom, and plunged straight into me. God, that felt divine.

'Hi,' said Tiff from the doorway, still with her strap-on poking out, 'I've got stuff from Thomas.'

I turned my head round, ready to ask for it, but Steven was too quick. He withdrew and indicated for her to smear it on his penis, which she did, before wiping the residue on her leg. When she left, he entered me again so we both felt the sticky mess. He rested one hand on my back and the other on Fiona's.

I know it sounds silly now, but at that point, I remembered how much food we'd brought in for our party. It had been intended for before the orgy, but I'd been thinking with my clit.

Steven must have been turned on by Tiff's special delivery because it didn't take long to add his load inside me. When he withdrew again. Fiona took his penis and squeezed the remaining semen out of it. I stood up and felt my boyfriends' two loads drip out of me. I licked up much of it, wiped the rest with a tissue, then went to warm up the oven. I passed Tiff, still thrusting into Samantha while spanking her, with Thomas watching intently, still half-hard.

It was only when I served up the first pizza that they reluctantly stopped, with promises to each other to continue later on. With everyone assembled back in the living room, I finally remembered to speak to Tiff.

'By the way, before I forget again, remember we talked about not using condoms?'

'The circle of spunk?'

'Eww, stop calling it that.'

'It's the wheel of for-tune,' sang Samantha.

I rolled my eyes. She cracked that one every time. 'Anyway, have you had any more thoughts on that?'

'We talked about it,' said Tiff. 'We're happy, aren't we?'

Samantha nodded in agreement. 'Yep, as long as none of that stuff gets near me, I'm fine with it, even once we're married.'

'That's brilliant. Help yourself to pizza.'

We relaxed as we ate. It seems we'd peaked too soon from the night's activity and it wasn't particularly late. Even Tiff had lost the motivation to use her strap-on. We barely managed to watch a film before heading to bed early. Our guests brought their own sleeping bags and lay down where they could. I don't think anyone even gave themselves a final orgasm.

It was probably for the best, as the others had trains to catch at lunchtime the next day, while Fiona and I had bar shifts in the afternoon. But we promised each other we would make the most of the morning before everyone had to leave.