My boyfriend doesn't know if he cam in me?

My boyfriend and I were having sex yesterday and we already had sex one time then later in the day we did it again and he didn't know if he cam bc after he does cum it usually tickles for him... Well it started to tickle and he said he didn't know if he can in me or not.. We didn't use protection. What does it sound like happen? Can you just not cum sometimes or? Help???