Why and how often should you drain that musky stuff from a pugs backside?

QUESTION: why and how often should you drain that musky stuff from a pugs backside? I need some info on what this is and why you are supposed to drain this nasty smelling stuff from a pugs behind. don’t know if DRAIN  is the right word for this but you squeeze below the dogs tail and this musky white stuff shoots out. what is the purpose of this very stinky liquid. Thanks.
 
ANSWER: I think you’re talking about draining his anal glands.. It varies from dog to dog on how often it should be done I believe and I’d consult your vet about it. They’ll do it for you as well but expect to pay.