Numerous occasions. My fave though was me, a mate and two lasses went off for a jolly drive during the summer. Ended up drinking (not the driver), and smoking and generally getting out of hand. Stopped off in the middle of nowhere to continue said festivities. Some back water, back lane from where you could see nothing but trees and fields.
My mate started getting a bit carried away with his lass inside ther motor so I thought, it's a lovely day out there, why don't we take this outside. Me and this other lass basically ended up starkers against the side of this van going at it hammer and tongs. Things are just starting to get critical when I hear a couple of voices I did't recognise! A quick scan round revealed that is was two auld dears who were out walking there dogs and given the direction they had come from had probably been getting an eye full for a good few minutes! I didn't know whether to stick or twist! Anyways, as soon as they'd leasuirely walked past the side of the van I took things to hasty conclusion!
The worst of it is, I've been busted in exactly the same manner since! Some may call it a mis-spent youth...I call it well fuicking spent!
And in answer to the question above this one.....a red telephone box on a main road, early evening an all like...never heard so many car horns in all me chuff!
What was your favourite childhood school yard craze?