Best definition
The concave area that is located beneath the shoulder and arm, also known as the armpit. Closely related to the

wenis and the wagina.

A father is explaining the anatomy of the human arm to his son.

Father – “Well son, this here flap o’ skin on yer elbow be yer wenis, and the thing on the other side be yer wagina.”

Son – “But Pa, what be this here thing under yer arm?”

Father – “Under me shoulder? Oh, that just be me wutthole, son.”

Wutthole: define #2
converse of the Wenis, a Wutthole in the soft skin on the inside of your elbow.
Dude i got my blood drawn last week and my Wutthole is still bruised.