When I was 15 I first discovered guys seemingly not using a public toilet for a legitimate purpose...before that I have never twigged on to this small fact. Feeling a little intimidated I went in the nearest empty stall, not wanting to get my dick out in front of all these guys; some of which were hot!
Once seated in the stall, I saw to my left a large hole in the partition about 4 or 5 inches across, being the mid eighties in an inner city, I was pretty used to seeing vandalism and graffiti and put it down to that, but in the course of my "visit", I noticed that there was something "going on" to left. The guy in there had stood, and was stroking his butt, and leg, and it was the movement of his hand that caught my attention. Being curious, I ducked my head about a little to see what else I could see and saw that this guy had his trousers pushed down to his ankles and had great legs, tanned and smooth, just my taste!. I thought it funny that he'd dropped his trousers so far as I never did, wanting not to sit on the seat- germs and everything! More curious- the town I lived in was very small with no gay scene to speak of; and believe me I'd looked everywhere for it, I saw that there were two men in the stall, there was another pair of hands rubbing up and down the legs of the tanned guy. He was then manouvered backwards toward the WC and I saw two men facing each other in the next stall, both with their trousers down both with nice looking hard ons, (about 7+") they were playing with each others dicks...
Nothign more than that happened and as I had friends waiting for me I sorted myself out and left the toilets, but I was very turned on, as you can imagine for a 15 year old. I never had much experience in "cottages" but seeing these two guys getting into each other, fuelled many wanks at the time I can tell you.
I don't condemn people for using public services such as those mentioned for sex, for many the option of meeting and making contact with people for sex isn't so easy, be it for family reasons or personal situations, or their job situations, there's a hundred and one reasons I am sure; be fair, you don't know what their story is