I'm watching Grace & Frankie, a drama comedy. In the first episode when Frankie's adult children came over to console their mother over her husband (and thus their father's) recent coming out news, they tried to reassure that she would get through this. Coyote is a former alcoholic and drug addict, and a sub teacher.
Coyote (to her mom): Look at me (implying that he's had his ups and downs but now is sober and can hold down his job). What professor scores coke off her student?
The second son: and he (Coyote) wasn't even sleeping with his student.
I think coke refers to cocaine, but what does score coke off her student mean? Similarly, is "score something off someone" a phrase?
According to dictionary.com one meaning of score is to "Purchase or obtain drugs illicitly", and "Any success, happy acquisition." I looked up "off", and it has an informal meaning of "from". Putting two and two together, it seems clear that score off here means, obtaining a happy acquisition, here coke, from a student.