Your boyfriend is an idiot. He obviously doesn't know rule one about getting laid repeatedly. It is that when ask by his partner about how she was for sex, a guy should always lie. He thought a bit about this when his answer went from decent to good. The real answer is wonderful, because no matter how bad she was at it, getting a guys penis into a woman is pretty wonderful. Lol.
Women worry about this a lot. I bet you didn't find his penis so magical that you loved having it in you, lost time and place in the universe, and asked him to leave it in, or stick it in again. On the other hand, if he asked, I bet you didn't or wouldn't say, "ok". You would have lavished praise on the size, shape, and awesome way that he used his penis. No?.
Anyway, he was probably just being honest. Sex is not something that we are born knowing all about. We, both men and women, basically know which body parts are usually involved, and sort of what to do with them. But how to be memorable, not to mention incredible, takes knowledge about how you work, what you like, desire to be better, and what he likes, how he works, and his desire to be better. You need to ask what turns him on, decide if it something that you are willing to do, and tell him what you want him to do, and see if he is willing to do it. Sex is just not laying there, opening your legs, and let him stick his penis into you. That is OK, but not great.
So, talk to him. Ask what would have made it fantastic. Try it. Enthusiasm goes a long ways.