Cute story. The back story is that they're "younger brother" and "older sister" (It's ambiguous if they're blood related). He got caught masturbating while sniffing her clothes, so he pretended that he was interested in cross dressing, which I assume led to stuff in previous chapters. In this chapter, she sees him cross dressing for a friend of his. The friend is surprised that he is so into it and he gets upset and leaves. The sister sees it and thinks it's an argument with his boyfriend. Anyway, she tells him she wants to teach him how to cum with only his butt and they plan to do it the next week. Then most of the sex scenes. Then at the final climax, he blurts out that he's in love with her. She tells him she loves him too. Later, when he wakes up there's a joke where he realizes he admitted to everything. Then she tells him that the reason she broke up with her boyfriend of three years was because her sex drive was too strong. He says he's not confident that he can satisfy her with his dick because he doesn't have experience using it. She laughs and says that he was happy when she told him he was cute when he was cross dressing and got an erection, and nothing has changed with how he can cum like a girl. Anyway, they promise to be together forever, etc.