In a nutshell, Shrimp Girls have a hot body but they're not beautiful.
Shrimp is because when we are going to eat a shrimp we are supposed to take its head off before eating.
Guy 2: A Shrimp what?
Guy 1: Shrimp Girl.
Guy 2: Shrimp Girl? How does it work?
Guy 1: Well, you know...wipe out the head, eat what's left