<human>: So I don't know why but this has been bugging me lately. 

When I was in high school I made friend with a lot of people a grade or two younger than me. This resulted in me knowing people several grades younger than me through association. When I was 18 I was hanging out with a mixture of guys and girls (there were maybe 6 of us.) The age ranges were 15-18. I was 18. One of the guys mentioned "the uncomfortable game" and I asked what that was and they said that two guys get closer and closer to each other (with the intent to kiss) and the first person to back down loses. I said I had heard of this game but it was people start taking off items of clothing and the first one to stop loses. They thought this was hilarious and two of them (both guys) started. The youngest guy was 15. It was funny for about 2 seconds and then I got really uncomfortable as I realized I was the oldest and the 15 year old was taking his pants off (still wearing underwear) so I left. Never saw anyone's junk. 

Ironically, I'm still friends with most everyone in the group (we are all in our mid-late 20s) including the guy who was 15 at the time. However, I still feel really gross and weird about what happened. It's been 10 years and I highly doubt they even remember it (I went to college soon after, but I know they continued to do this kind of stuff all through high school.) Did I do something wrong? Anything illegal? It's been bothering me a lot lately.

Can you give me the gist of the text in a nutshell?
<bot>: When I was in 18, I saw a 15 year old guy get down to his boxers in a social setting (with other people there) and realized I shouldn't be there so I left. Did I do anything wrong?