[¯|_(ツ)_|¯]

Hey,

I would talk to your friend about this. While it is okay to be sexual with your consent, it is inappropriate to be doing it in front of other people in a school setting. It could get you both in a lot of trouble.

I'd let your friend know that you're glad he's comfortable with his sexuality but please do not act sexually with you in school like this. You can say it makes you upset when he does this. You can let him know the things you are okay with either in public or in private. Make sure you are firm with this boundary. If he doesn't respect your boundaries, he's not a good friend and not someone you want to hang out with anyway, because a true friend is respectful of boundaries.