drunktender
Adj.: a designated driver that must also tend to the needs of the drunks they are driving around. Drunktenders are usually requested to do more than drive, i.e. help the drunk find their keys, pants, glasses, cell phone, dignity etc. A drunktender may also intervene a stop a fight or prevent a bad hook-up.
"no thanks bartender, I'm not drinking tonight, I'm the drunktender for these jerks"