1. Hooking up with someone sober on a weekday (rather than weekend).
2. Criteria that automatically qualifies someone as a girlfriend or boyfriend.
Tony: That girl from the gym came over to my place last night to watch a movie, and we hooked up.
Jack: On a Tuesday? I didn't know she was your girlfriend.
Tony: No way, dude! She's not my girlfriend.
Jack: You got weekday sober ass. That's a girlfriend.