When I was 13 , there’s this swimming place with two Olympic sized pools there and I used to go there a lot. I’ve seen all sorts of common-goers , retired men , teens with nothing better to do , college students looking to get fit. But never had I seen something like this. I’ve always been an a** man , even at that age. There was these two 11 year old girls who seemed to be sisters and I was resting at the side of the pool after doing some laps right under the diving board. The two girls were doing short laps (instead of a proper lap , they swam from the left side of the pool to the right and vice versa) , I stayed submerged while checking out their cute butts. Some guy about my age who I could only assume is there brother or cousin. Showed up and coached them. I decided it was enough rest and I continued swimming. Later , under the same diving board , I looked to find the two cute girls again. They were both resting next to another diving board about 10 ft away from me. They were facing the wall , arms on the edge of the pool and relaxed. The coach was talking to them , right behind both of them. I submerged again , but this time the coach submerged as well and played with the two girls’ asses for a good 10 seconds , I stayed submerged and undetected the whole time. When we both surfaced at the same time , the girls didn’t bother and kept talking. I found this weird and some the coach got up and left the pool. There was no one else at the pool or around the pool, so I went up to the two girls and started asking them about the situation. They didn’t seem to care about what the guy did. The whole time I was slowly reaching for the cuter one’s a** , she was surprised but stayed quiet , we kept talking until I felt what I was doing was pretty fucked up , I said goodbye and left. I never saw them again. I think back to it time to time as to what the hell was I thinking and also to fap to it.