A Melvin
A Melvin is like a weak peenie that doesn't even have the guts to come out. It just plops out like a sad excuse for a snack.
Bro, my Melvin was worse than my dad's second marriage.
I had a Melvin so weak, my dog laughed at me.
My Melvin was like a leaky faucet, slow, annoying, and never done.