Three altar boys are standing in the snow with their pants down around 
their ankles. They have their penis' in a snow bank.

Sister Margaret sticks her head out the window and says, "Boys! Boys!
Whatever are you doing... you're going to catch pneumonia.  Put your 
penis' away."

The tallest altar boy turns around and yells, "Sister Margaret, don't 
worry, we know what we're doing.  Father Porter always likes a couple
cold ones after work...."