Pat the Roo
A literal phrase used at nature reserves where there are tame kangaroos around that you are able to pat. Although it is a completely innocent phrase it still sounds like a euphemism for masturbation.
"I'm going to go Pat the Roo"
"I don't need to hear that!, just clean up afterwards"
"What?"
"I don't need to hear that!, just clean up afterwards"
"What?"