Vomiting into a toilet -often violently and for an extended time- whilst holding its rim like a steering wheel.
Australian Prime Minister, Kevin Rudd, when asked at a press conference about his recent bout of food poisoning: "Yes, I was driving the porcelain bus half the night."
by Ozymoron October 02, 2009
When you've had too much to drink, and you wind up with two hands on the opened toilet in a kneeling position puking your guts out.
Man am I exhausted! I drank too much and was driving the porcelian bus all night!
by Ralph, the bus driver January 03, 2004