What do you mean? You're a master and not a guest. It's just untrodden territory for the moo. Masters were all male, and as far as he knows with his past experiences, being gay was not normal (in his convo with Luke). Not to mention the nature of those relationships.
The real question is: How will they initiate the scene? Asterion imo is unlikely to bring it up; he'll probably be stuck at some 'Am I deserving to indulge in such pleasures? With the master, no less?' spiel in his head. If it is you who does so, I'm betting that the speedrunner route will have some fun shenanigans.