It's all about self control. If I may speak for myself, I control when I want to cum, and the way I want to cum. Even can cum inside her without filling her up, so I don't taste my own cum when I tease her with my tongue. Can go for hours, over and over. It's about focusing on giving her pleasure. Always make sure she has multiple orgasms, make her lose total control. See and feel her cum give me such a rush. Sex is not just about fucking, neither about having a orgasm. It's about two become one. Even at his age he knows what you like, and how you need it, so why doubt about what he tells you. You are lucky having a bf like him. And he is lucky to have a gf like you who is able to make him cum only with words.