❌HELP ME PLEASE❌

Alright guys, I've gone down on my boyfriend a couple times now, and I really enjoy deepthroating him and he enjoys it too. But I can't help but let out a small gag whenever I get it all the way in and when he tries to headfuck me or whatever it's called, I gag sometimes. It's super embarrassing, do you guys have any tips on how to prevent gagging or how to go deeper??