O Muscle 

The muscle in a woman's tummy that contracts during an O.

Dude: Is that a six pack?
Chick: No, it's a highly toned O Muscle.

O Muscle by B.B. Smith October 20, 2008

O Muscle 

The muscle in a woman's tummy that contracts during an O.

Dude: Hey, you have a six pack.
Chick: No I don't, just a highly toned O muscle.
Dude: Well, let's pour some honey on it. . .

O Muscle by B.B. Smith October 10, 2008

O Muscle 

The muscle in a woman's tummy that contracts during an O.

My law partner has a remarkable O Muscle.

O Muscle by B.B. Smith October 20, 2008

O Muscle 

The muscle in a woman's tummy that contracts during an O.

Mr. Smith: You have a six pack.
Miss Smith: No, it's just a highly toned O Muscle.

O Muscle by B.B. Smith January 20, 2009