A baked or fried snack similar to french fries but made of fish
OR
A joke that was popular for a long time, thanks to South Park. The joke accuses people of being a 'Gay Fish' if they enjoy eating the fried fish.
Person one: What would you like to eat tonight?
Person two: I think I would like some fish sticks!
Idiot one: Do you like Fish sticks in your mouth?
Person: I do, how else would I eat them?
Idiot one: LOL YOU'RE A GAY FISH BECAUSE FISH STICKS REFFER TO FISH PRIVATES LOLOLOLOL Person: ...