Continuity mistake: The airbag on the patrol car deployed when the little car struck it from the side. It deployed a second time a few minutes later when the patrol car crashed into something else.
Revealing mistake: When the girls are driving away from the popular girls, after they get juicers, you can see in the car that they are stunt drivers. The facial features are different and Yancey is taller and skinnier.
Continuity mistake: When Julie is hiding in the shower and Steve turns it on, there's a smudge of mascara on her cheek in one shot, then the next it's gone.
Continuity mistake: The patrol-guy tastes the Coca Cola, and the girls go back to the house. But when Stacey comes, there is no Coke in Julie's hand.
Answer: Hooking up is to get together for sex or a relationship.
Grumpy Scot