Momo became my adult stepsister when our parents married. Cheerful and outgoing, she treats everyone warmly—the complete opposite of a shut-in like me. But because she does not see me as a man, she lounges around the house without a care, constantly exposing her thong and bare ass. Having never seen a naked woman's ass before, I cannot stop fantasizing about hers until one sweltering day I finally reach my limit.