What happened is he apologizing for nutting but dude she obviously didn't want to do it by the reaction you should if quit. Also is this dude a virgin?
A development. She said shes inexperienced so he should ignore that gnashing and keep on going. Its obvious that she was nervous bcs she only know how its feels in her manga and not irl.
Too bad that he lost his caring girlfriend. But well he did got a busty one afterwards.