Since we are having R-rated fun here, I don't know if anyone remembers one of my very first posts on the original Pierre Tremblay board...I asked everyone for their horniest moment in the movie.
For me, it was when Jack & Ennis were standing on the landing, Ennis introducing Jack to Alma. First off, you could practically see the smoke coming out of their ears--and then the thought of what was going on their pants drove me over the edge. Still does, every time I see that scene. Wowie, hot, hot, HOT!