Doing a 'Moonie'.
I was driving back from town this afternoon just before it started to get dark, when rounding a sharp bend in my road, I noticed out of the corner of my eye, there were 3 young lads around 12 or 13, making a lot of noise, shoving each other about and laughing loudly.
As I drew level with them, one of them ran out to the edge of the kerb and I thought he was going to run in front of me for a second, but he didn't. Instead he pulled his trousers and underpants down, bent over, and flashed his bare bum at me!
Stupid boy. What on earth was that all about?