I don't really see an issue with teaching the boys about their parts and what to look out for and the same for the girls. Seems really fucking odd to tell them about fapping tho. You don't want a bunch of teenage pregnancy and they might think fapping is a good way to get them release without hoping they'll wrap it up but it still makes no sense to take that upon yourselves as a teacher aka glorified baby sitter. It's tough to know when these things come from good people with good intentions and when it's a clever pervert who just figures out how to work the system.