It was in 2015 in the downtown of Austin, Texas at a club named The Market. They had a indoor rooftop space and two separate bars. Monday to Thursdays the rooftop and it's bar was closed (but not locked).

So people could still get drinks from the downstairs indoor bar and carry it to the rooftop bar. The rooftop bar would have all lights turned off, so there was only some light coming from the surrounding buildings and the cars/streets.

So, one fine weekday (it was probably Wednesday) in 2015, my then boyfriend and I went to this bar and were having a drink indoors and until then we didn't know about the unlocked rooftop door. We saw this other couple enter the bar, get the drinks and head straight upstairs. We were intrigued and after a few minutes we both went upstairs too. We tried to open the door to the rooftop and voila! it was not locked.

We saw the other couple in a dark corner behind the stacked chairs and tables, making out passionately, and the guy was fingering the girl who was in a short dress (and probably no panties). They saw us and got uncomfortable and stopped. We smiled at them and gave them a thumbs up, and we also started to makeout in the other corner. So now they got comfortable and started going at it again. It ended with both me and the other girl giving blowjobs to our own boyfriends.

After that, the 4 of us hung out and had more drinks and went on to become very good friends and started swinging.