I was recently in the middle of a conversation between my younger brother and my mother. They where discussing dogging, when my brother came out with the term 'seagulling' I asked him to explain...
He said "'Seagulling', is when your having a wank, whilst watching a couple dogging, then you shoot your load on the car window, it looks like a seagull has shit on it."
I don't know what freaked me out more. The fact he said that in front of my mother or the fact that my mother already knew what it meant.