butt monkey

noun2

1. •
   (US, slang) An object of abuse and ridicule; sometimes, especially, a prison bitch.

   • Xander: I'm sick of being the guy who eats insects and gets the funny syphilis. As of this moment, it's over. I'm finished being everybody's butt monkey! — 2000
2. •
   (US, slang) An annoying and irksome person.

   • I still prefer Butt Monkey User Group myself. — 1993