How to get an orgasm while being eaten out

Okay, TMI but, I masturbate some times and it takes me less than 5 min to orgasm. It's so fast and so simple. Can orgasm maybe 3-4 or more times in one round. Anyways, last time my boyfriend ate me out I couldn't orgasm. I was close to. I cannot orgasm with something inside me if you're eating me out so, he was sticking his fingers which were hurting me. I was trying to hold my breath while making the uglies face I can imagine but still we were just close but never orgasm. Is there any tips? I wish I could tell him how but I'm afraid to say that I masturbate. Maybe he'll feel bad that he can't make me orgasm but I can myself. Any help please?