Define Fish Hook Meaning

Fish hook- a sexual manoevre in which one person uses a finger or a thumb to form a crudely improvised hook inside the orrifice of another, followed by exerting an outward, stretching pressure on said orrifice.

While performing intercourse "doggie-style" this maneuver involves the pitcher inserting his curled finger into the catcher's mouth and pulling back to degrade the subject or cause pain.
A "double fish hook" involves the same maneuver using both fingers.
A "rusty fish hook" involves fingering the ass of the catcher prior to insertion of the finger(s) into the mouth.

Putting a finger in someones mouth while trying to hurt them and then pulling as hard as you can to rip their cheek. This resembles a fish being hooked so is called the fish hook.
As seen in The Gangs Of New York

using your index finger to pull down a girls shirt in order to see her boobs.

After sliding your finger into the cathedral you then curl your finger and pull back.

when you're getting head from a chick and you have a dick piercing. just before you blow you catch the piercing onto her cheek and reel 'er in and watch her squirm and squeal. that is what i call "catch of the day"

Kicking a guy in the nuts from behind and make it so your toe connects directly with the scrotum, gooch or tip of penis. Also known as a candy cane.

while having sex with ones partner via doggy style, slide index finger into anal cavity. Then remove finger and insert into her mouth, pulling on her cheak.

using your index finger to pull down a girls shirt in order to see her boobs.

When one with braces attempts to give oral sex to a male, and the sharp metal snares the foreskin of the penis, resulting in awkwardness, embarrassment, and a great deal of pain.