How do actresses maintain their composure and professionalism while fucking these old dudes and ugly dudes?

Most importantly, how do Japanese directors convince these beautiful JAV idols to do scenes with these ugly or gross guys who are doing stuff like licking, tongue kissing, and all kinds of nasty shit lol

I mean the girls are usually stunning, young, and seem super into it even when the guy is some balding old man or a weird looking dude. Do they use some special training or mental tricks? Or is it just about the money and professionalism?