Sam and Tom got back from their run. By now, their runs had generally become pure runs - after their first sex-filled running encounter, although if the opportunity arose, they weren't afraid to rise to it! The sex would come after, or before.
I [Tom] had previously asked Sam if Kate, her flatmate, was seeing anyone. Sam said she wasn't, but one night after a few drinks, that she [Sam] had persuaded Kate to go onto the dating sites and hunt for FWB as she was not into hookups. It turned out that Kate had struck lucky and found Pete, who she'd been out with on a few [vertical and horizontal] dates.
When we got back to Sam's house, we could hear moaning and groaning.
Tom said, "I didn't think Kate was in tonight?"
Sam said, "Neither did I, but it seems that Kate is doing Pete in the lounge."
I replied, "What happens if one of you catches the other at it?"
Sam said that it rarely happened, but she went in the back door and fingered herself until Kate was finished.
I hadn't paid much attention to Kate's figure until now, but through the door glass, I could see Kate riding Pete reverse Cowgill. Her breasts were probably DDs - a bit smaller than Sam's, and Kate's pussy was shaven - and filled with Pete's sheathed dick. Looking at Kate and Pete fucking, made my cock grow, and I could see Sam starting to finger herself.
I took Sam by the hand, and we walked round to the kitchen door. On the way, I asked her how "open" she was with Kate. Sam said there were times when they'd been naked in the house - but nothing sexual between them and they had never snogged.
Sam gently unlocked and then opened the door. We walked in holding hands and gently closed the door. Sam took my hand and said, "You said .." and put my hand down her running shorts. In the background, we could hear Kate and Pete going harder. My hand found Sam's wet pussy and started rubbing it. Sam slid her hand down my shorts and found my hard cock and started stroking it. Sam leaned over and put her tongue into my open mouth, and I returned the kiss and started Frenching. My fingers were probing deeper into Sam's pussy as her hand was stroking my cock harder.
In the background, we could hear Kate's horny moans as Pete fucked her harder.
Sam said, "fuck me," and undid my shorts ties and then dropped my shorts. I took my hand out of her pussy and pulled down her shorts.
Sam then pulled off my top, dropped down and kissed my balls. She quickly worked up to my head and the gave me a quick throat. I reached under her tight top and briefly fondled her tits before lifting it completely off. Now, we were completely naked against the kitchen wall with the horny Kate and Pete fucking in the background.
We resumed kissing, and I put my cock against Sam's pussy and started rubbing her wet entrance. The background fucking noise was getting louder as Kate seemed to be on the verge of cumming - this was turning us on knowing that a couple was fucking nearby.
Sam stood up a bit higher and guided my cock into her wet pussy. I dropped down a slight bit and pushed up. Now my cock was deep in Sam's pussy, and my tongue was in her mouth. Sam's nipples were pushing against my chest. Our Frenching deepened as I started thrusting into Sam. We could hear Kate groaning as she started cumming. This made Sam and I even hornier: my cock was growing, and Sam's pussy started to grip my cock harder.
We heard, "FUCK... FUCK! FUCK!" as Kate came on Pete.
Sam kissed me harder, and I thrust deeper into Sam. Sam kissed me harder, which I returned, and her pussy squeezed my cock. I thrust deeper and faster into Sam and her pussy started squeezing me harder as my balls started to tighten. Sam started to moan as her pussy started pulsing my cock. My balls started to twinge as I started to cum into Sam. In return, Sam squeezed my cock and pulsated as she orgasmed.