Flop dongler 

a penis of epic size, very big in length and girth.

WOW! That is a massive flop dongler you have there, you could kill a gorilla with that!

Flop dongler by J&A8991 October 17, 2012

flopdonger 

N. (comes from the latin word flochilofusdongi which means horse dick)

A large soft penis.

my flopdonger is itchy. Clay hit adam in the face with his flopdonger

flopdonger by the supervisor March 31, 2004