They happen because more blood goes to your snake. Simple.
It's a reflex.It happens when you move about when sitting down with tight jeans.
It also happens when you see a hot chick not a GUY.
Or a DOG.
I hate getting those in school. I go to an all boys school, and it won't go away.
In England? The Stamford endowed Schools?
In England?
My ancestors are an English noble family.:P
stop looking to your dog