best ways to teach cis gay guys about trans anatomy?

So I've gotten more into casual hookups lately, and for nearly every guy I've been with or talked to, I'm the first trans guy they've been with. I'm okay with this because someone's gotta be their first lol. So I typically go into these scenarios knowing I'm going to have to teach them at least somewhat about what to do, but I haven't 100% figured out the best way to explain things to them.

Do you guys have any go-to methods or explanations that you use before or during these scenarios?