In this adult sibling role-play, a cheeky sister worried about her small breasts keeps making her brother massage them, claiming it will help them grow. He always gives in to their soft feel, but his self-control is finally reaching its limit. Her sensitivity rises with every session until she becomes just as horny. What normally ends with a simple breast massage finally crosses the forbidden line, turning the clinical rubbing into slow, erotic foreplay that leaves her pulling orgasm faces with her pussy soaking wet.