What is Lumpy Platypus?
1.
A sexual act in which a man's partner pulls forward the foreskin and pinches it closed over the end of the flaccid phallus, causing the organ to resemble a platypus. The partner continues to try to keep the head of the phallus hidden while said phallus becomes engorged.
"She was giving me a lumpy platypus, and the turtle popped its head out and stabbed her in the eye!"
See