Performed by adults in a sibling and school-swimsuit role-play. He agrees to teach his sister to swim because she hates swimming class, but the sight of her breasts in a school swimsuit gives him an erection and leaves him unable to concentrate. She notices his panic and asks how to make it go down. He admits that he wants to fuck her, but she recoils at going that far. Just when he thinks he has ruined their relationship, she sees how crushed he is and offers to rub against him without penetration.