neck elbow
A considerably large adam's apple, especially on a woman. If the subject has a skinny neck in addition to a prominent adam's apple than the "elbow" appearance is even more apparent.
Dude 1: Did you see the neck elbow on that chick who was hitting on me?
Dude 2: Yeah man. I bet she has a dick.
Dude 2: Yeah man. I bet she has a dick.