Adult role-play. Hearing my adult sister and her boyfriend having loud sex leaves me so horny that I buy special lingerie and decide to find a boyfriend of my own. While I am happily trying it on, my sister’s boyfriend catches me in my underwear. He does not pounce immediately, making me think he might be a gentleman, but we end up having sex anyway. Our chemistry is so intense that we continue meeting for repeated creampies. The lingerie meant to help me find a new boyfriend becomes my uniform for cheating with my adult sister’s boyfriend whenever she is away.