Chris: "Ah, yes I did. Of course those two are always DFA."
The sesh/session here refers to a period where 1 or more people are smoking marijuana.
Caroline: Really? DFAS to cheer you up?
Savannah: LETS GET DRUNK AND PARTY!
Paige: Na, I don't want a hangover , I'm working tomorrow.
Savannah: Oh, DFAS instead?
Paige: FUCK YES!