Sorry if something like this has been posted already.

A bit of background: I'm still a virgin. I have, however, read numerous erotic stories and articles/editorials about writing sex scenes. I'm still not very confident in myself though, hence this post. I'm writing literary fiction, not erotica, but there will still be several sex scenes. Most are M/F, but my (male) MC is bi, so there will be at least one scene of him with his male lover. With that out of the way, what are some tips/advice you guys might have for writing sex scenes? In general?