Q. What happens to a dog in the fog?
A. It disappears!!
this is to discribe leaving qiickly after an evening out. When you know you have had a little too much to drink and need to go home but your friends are trying to keep you out!
Everyones happy drinking away, they turn round and you have left half your pint on the bar and the door is flapping in the wind.
this is commonly known as " doing a dog