Flatulence is a fairly taboo subject for U.S. advertising. Not so in Canada, apparently. This public service announcement from Ontario Ministry Health likens social smoking to passing gas in public.
The intention appears to be to shed the spotlight on lame justifications for "social smoking." In execution, it's hard to get past the voluble sound effects. However, it may make some Canadians a bit more self aware the next time they ask someone to go out for a "smoke."