b.) to wear a lot of makeup. Figuratively speaking, the girl literally takes a heaping scoop of makeup with her hand and smears it all over her face. not literally of course. people who scoop are most likely unatractive without their make up, and are also sluts.
John: (Scoops Frank) Scoooooop!
Frank: ah! jesus christ, what's wrong with you?
b.) Mark: Timmy, who do you like?
Timmy:..... Emily! okay?
Mark: Are you kidding?
Timmy: no, she's hot.
Mark: No way dude. She scoops!