We have been dating for a year and just recently started doing more sexual things. He (17m) has “finished” in his pants a few times from me (16f) just placing my hand on it over his pants. The first time it was cute, but it has happened 7 times now. He says he gets turned off after and so we stop doing anything. We have only made it as far as pulling his underwear down once before it happened again. I want to be respectful, but I’m also frustrated that I feel left out. The last time it happened as we were just kissing. What can I do to help him not immediately finish?