To hang upside down on a bar or branch and stroke one's member until they jazz in their own facial region and/or mouth.
"I did so good on that test I had to go monkey myself this afternoon"
"I won the lottery and the only thing I wanted to do was ]monkey] myself"
"I totally banged this 10 last night and immediately monkeyed myself after in sheer satisfaction."
"9 out of 10 doctors agree that monkeying yourself is the most satisfying form of birth control."