If you're a male writer but you have a female heroine (with her POV throughout), but it gets to a sex scene, won't it seem rather odd from your own POV as a straight male writer if you are imagining her in her shoes? I would think it would be rather difficult to really picture it from that side, and you might personally prefer to desribe how your female protagonist is like. But then if you switch POV to the male just for that scene, won't the sudden change seem somewhat forced or artificial?
What does one do?
Presumably one is a writer, and does what writers do--make shit up.