The step-sister thinks it's cute that her little brother gets excited when he sees her body. She gets carried away and teases him by leaving the door open while taking a bath! The little brother is confused when he sees her like that, but he gets an instant erection! Unable to resist his sister's big washing ass, the little brother hugs her from behind and immediately fucks her! While trying to calm his out-of-control brother, the sister also starts to shake her hips... and it quickly develops into a forbidden incestuous relationship!