A hang up fail is what occurs in the least opportune moments where you press the hang up button on a call but because of a laggy phone or dirty fingers the call doesn't hang up often resulting in the person on the other end of the line listening to you for a while after you hang up.
You:"okay I gotta do some stuff talk to you later" *presses hang up, sits on toilet... farts loudly*
Person STILL on the line: "I can hear you"

Hang up fail!

Or

You:"okay, talk to you later" *presses hang up button* Jesus, what an unimaginable BITCH!
Person STILL on the phone: "what the F**K?!"

Hang up fail!
by Twitchingdeadgirl August 14, 2014
Get the Hang up fail mug.