In 'Lust Theory,' a busty, horny landlady greets her tenant late at night, clad in seductive lingerie. She fingers her wet pussy, moaning, before inviting him in. She continues her self-pleasure, teasingly, as he watches. The tension builds, and she can't resist any longer. She straddles him, feeling his hard cock through his pants. She grinds on him, whispering dirty words, before taking him deep into her mouth. She rides him, her big tits bouncing, until he explodes inside her, filling her with his hot cum.