It’s normal. Just keep composure and don’t be creepy about it.

Try not to lose sleep over it. As @violetraven@lemmy.blahaj.zone said, don’t call attention to it and you’ll be fine. It’s even less weird than getting a boner in the middle of your physics presentation. Here, you at least have an obvious reason for the boner.

I usually just think of a generic chair and it goes away.