Basically, the fic has me thinking like this:
Remus: Shall we have a few alcoholic bevarages, then? Because I must say I find you rather appealing to the eye and would like to initiate sexual intercourse with you, if you don't mind.
Snape: Why, not at all! It would be my pleasure, in fact, if you would insert your erect penis into my anus or permit me to do the same to you. Perhaps we could even engage in some oral stimulation!
Remus: Oh ho ho! You do have the very best of ideas, Severus. I must say, I don't do this often, but for you I am willing to participate in a one-time homosexual sexual encounter.
Snape: Let's away to your room, shall we? I fear some overly enthusiastic young folk might knock on my door wishing to converse with me about their educational aspirations.
Remus: Oh ho, how droll!
Snape: How droll indeed. Shed your clothing, now.
Remus: It is shed.
Snape: Oh, Remus, your body is delightful.
Remus: Oh, I've ejaculated!
Snape: Well, look at that, so have I.
Remus: Nice, wasn't it?
Remus: Ta, then!
QWP from here.