Drilled my best friend’s girl on the terrace while he hosted a party for our friends in his apartment [Bull’s perspective]

Hello, I’m in this relationship with my best friend and his girlfriend for almost 7 months now and this happened quite unexpectedly.

We were supposed to meet as usual last Sunday, have our usual fun and chill. But some of our college friends were in town and we decided to meet up in my best friends apartment. It was kinda disappointing coz it’s been a while since we had our sex, but whatever.
Our friends came in the evening and it was quite nice to catch up with many. It was all going good until the topic of the relationship of best friend and his girl came up, they were admiring how long lasting their relationship has been, and how are they couple goals and all.
It was quite amusing coz it’s been was right next there,silently listening. Well, it’s a thankless job haha.

This conversation triggered me and I just pulled my friend aside, asked her if she wants to do it now. She thought I was have gone crazy but I could tell she liked it too. Just some little dirty whispers abt how exciting it is sneaking behind everyone’s back and having sex with his boyfriend’s best friend and she was convinced. I told my friend this too, and he had something of a similar reaction. So we made an excuse and sneaked out. We went to the cellar first, to my car, but there were ppl. Risky. So we went up to the terrace, riskier tbh, but idk, if it was the cold breeze or the openness of the area…it was a turn on. We immediately started kissing and groping each other. We didn’t dare get completely naked fearing someone would walk in on us. She blowed me under the open sky and I was on cloud nine. I returned the favour, and then she leaned against the wall and I fucked her from behind. This has to be the roughest and clumsiest sex we had lol…constantly vigilant. I came inside her…and she walked back to the party with my cum in her. The moment we entered the apartment, my friend had a curious look, I just gave a nod and I guess he would’ve been instantly hard. I had to leave coz a couple of friends decided to crash in for the night. But that night my they both had sex with her telling him the details abt our little adventure.