Uraraka teased her unpopular younger brother as a joke. Misinterpreting the joke as an invitation, her virgin brother immediately penetrated his sister right after their parents left. Although Uraraka climaxed from the sudden intensity, her inexperienced brother didn't notice and continued to thrust wildly. Despite reaching orgasm multiple times due to the relentless pistoning sensation, she couldn't resist and was made to climax repeatedly until their parents returned home.
