"playing it off" or "played off" just means you are executing or executed the play. A recent example would be where I got 10X points at the Deadwood Mountain Grand weekend before last. They have a blackjack console in there that's a 99.43% base game. The card is worth .4% so 10X made it 4%. The 10X lasted two hours on Friday night and 2 hours on Saturday night. So I went in on both Friday and Saturday nights and "played it off." At the speed the machine plays it was $800 in EV but I actually made $650.
Don't anyone go flying off to Deadwood. The play is over.