Carla 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!
I [Tom] had previously asked Carla if Kate, her flatmate, was seeing anyone. Carla said she wasn't, but one night after a few drinks, that she [Carla] 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 Carla's house, we could hear moaning and groaning.
Tom said, "I didn't think Kate was in tonight?"
Carla 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?"
Carla 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 Carla'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 Carla starting to finger herself.
I took Carla by the hand, and we walked round to the kitchen door. On the way, I asked her how "open" she was with Kate. Carla said there were times when they'd been naked in the house - but nothing sexual between them.
Carla gently unlocked and then opened the door. We walked in holding hands and gently closed the door. Carla 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 Carla's wet pussy and started rubbing it. Carla slid her hand down my shorts and found my hard cock and started stroking it. Carla leaned over and put her tongue into my open mouth, and I returned the kiss and started Frenching. My fingers were probing deeper into Carla'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.
Carla 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.