I think in summary, that while many stories have good writing of the scene descriptions and can work really well for what they are intended for, they often have problems making that leap to being a great story by lacking conflict and tension. Surprising the reader with what will happen next or make them anticipate what may happen as tension increases until it crests when someone wins, and someone loses. Losing is debatable when the loser ultimately has an orgasm but in the case of a Straight to Gay or the like story it often is the successful conversion or turning out.
Have you read Percxyz's stories? He is by far my favorite author with the themes that you have described.
Locker Room Lesson is a hot short story, so you can get a sense of his writing style.
Dominated by Doug is novel length and was already linked here.