(noun) A person, usually a girlfriend, who is dirty, slutty, and sexually uninhibited, who will do anything and everything you ask her, except she'll do this only for her boyfriend/husband. She doesn't sleep around. She's a dirty little whore, but she's your dirty little whore. She's a slut that you keep in your pocket. A pocket slut is different from a regular slut who will be a dirty little whore for anyone who asks her, with no commitment required.
"Ah, man! Cheryl let me tie her up and do anal on her last night. Damn it was hot!"
"Sweet, dude! She seems so pure and innocent around everyone else, but when you get her alone she's a total nympho whore! How do you do it?"