Soo much cum

I'm 17 yrs old and I recently got into a relationship. Me and my boyfriend were making out and he was fingering me. I was super wet and I had came a couple times. He wanted to eat me out, but there was soo much cum, that he didnt. Then he tried me sitting on his face and he couldn't breathe because there was soo much cum. I got a little upset but I didn't show it. I didn't want to forcw him either. How come there was so much? What do I do next time when he was to eat me out?? Please help.