Your third leg 

Did you know your penis is an undeveloped third leg, crazy ik... but hear me out.

Joe: Yo, my penis is hard!
Sam: Dumbass, Thats your third leg!!!

Your third leg by iheart7 February 21, 2023

Third Leg 

An incredibly large penis. Syn: dick, cock heat-seeking moisture missile, throbbing python of love, belly busting giggle stick.
Ant: tadger, prick.

...And then Jaxom whipped out his Third Leg, and boned her up.

Third Leg by Chaoslight November 11, 2003

thirdle 

The phenomenon of overcoming the ('third' beer 'hurdle') in which one transfers from a rest state into a euphoric state.

Dan has just gone over the Thirdle.

thirdle by Cheong April 15, 2014

A third leg

A man with a penis that could pass for a third walking leg. It is long and full with a mind of its own.

He was short but he surely had a third leg based on the way his pants were positioned.

A third leg by fuquaystone May 10, 2018

Third Leg Salute 

In military terms, a male erection. Usually used by veterans and serving members of the military to explain the tent in their camo pants.

I gave that lap dancer a third leg salute.

Third Leg Salute by DaErYn May 24, 2021

Restless third-leg syndrome

1. The inability to control one's penis, and, therefore fucking everything in sight. Generally it is men who are afflicted with this disease.
2. An excuse whoring men give for being unfaithful.

"Baby, it's not my fault you caught me with the Maytag repair man in a 69! It's my Restless third-leg syndrome acting up".

Restless third-leg syndrome by BaJinxy August 29, 2007

third leg 

An unreliable appendage found on males of upright-walking species. More prolifent in warmer areas, especially in the native tribes of Africa, this appendage is not often used for mobility. The original third leg lost its foot in a shoe thousands of years ago and now all later third legs constantly search in shoes for the long-lost foot. The third leg becomes excited when it approaches the shoe found in between the legs of the female of the species, or the boot found on the posterior end of either the male or female of the species. The leg pokes around the shoe or boot looking for its lost foot, and culminates its search by spewing its tendons into the shoe or boot, trying in a last-stitch effort to reconnect the foot.

In prison, the larger males spend most of their time searching for their foots with their third leg for hours among other inmates.

third leg by Dub P January 10, 2007