A scale used to determine how infatuated you are with a certain someone.
1. They're pretty chill.
2. I'd ask them out to a movie.
3. I'd go out with them.
4. I'd shove my erect penis up them all day until we both ejaculated everywhere.
5. Marry.
Person 1: Bruh, you like that girl?
Person 2: Kind of. She's like a one on the crush scale.
Person 1: I got you bruh.