Hang Over Time Off. Similar to paid time off or P.T.O. H.O.T.O. can be used so that you can show up to work a few hours later than usual, or skip the day all together. Usually the result of a long night of drinking.
Damn I was out late last night I need me some H.O.T.O.
I drank too much gonna have to call the boss for some H.O.T.O.