Reverse Penis 

A reverse penis is a vagina.

Her reverse penis is the opposite of a penis.

Reverse Penis by Rusy Shakelford July 31, 2007

Reverse Penis 

any sort of sexual inuendo involving a tail on a male person

"I do have a rather large Tail"
"I don't want to hear about your reverse-penis"

Reverse Penis by Taylor Action September 11, 2005