A once-common game played mainly by boys in their first year of secondary school at Inverkeithing High School in Fife, Scotland. When on a crowded double-decker bus, one must stand at the bottom of the stairs between the two decks and not move. Others will stand behind you, and as many people will try to cram themselves into that tiny little space as possible. Some will get a bit too excited, attacking people and jumping off the top deck, inevitably leading to a riot.
"I heard Chris and John got into trouble yesterday by playing Pile-Up."
A shortened form of "guidance teacher". Perhaps only used by guidance teachers.
Miss Forbes: "Well, that's your last PSE lesson of first year!"
Miss Forbes: "Who was that!?"
Miss Forbes: "Well, I'm no gonnae be your PSE teacher anymore, Emilly, but you've forgot that I'm still your guidy!"