slang To vomit profusely into the toilet, usually as the result of drinking excessive amounts of alcohol. John was driving the big bus for the rest of the night after his seventh tequila shot.
drive the big bus
and drive the porcelain bus and ride the porcelain bus
tv. to vomit into the toilet. Harry’s in the john driving the big bus. I guess that “drive the porcelain bus” refers to holding onto the toilet seat while you vomit.