When you arrive in prison and beat down the biggest prisoner in your cell block so everyone will know you're not easy pickings. Occasionally known as a "PHD".
"Paul wasn't looking to be anyone's bitch while he did a stretch at Riker's, so he gave the alpha a prison-howdy-do and got through his sentence with no trouble from the other prisoners."
1. A classic childrens television show from the 1950's featuring Buffalo Bob, a ventriloquist who had, among characters, a wooden puppet named Howdy Doody.
2. What you say to the steaming pile of turds in the toilet, when you turn back to look at them.