punk out

Verb

 * 1)  To give up or cravenly abandon something difficult.
 * When the going got tough, he punked out.
 * 1)  To treat as a punk (either as a worthless person or the bottom in a male-male relationship, especially a nonconsenting prison relationship).
 * He knew if he didn't stand up for himself, he'd be punked out by someone stronger.