look up any word, like the eiffel tower:
 
1.
When a male straddles a female's face on all fours and she sucks his testicles while masturbating him with her hand.
Dude, last night I walked in on Katrina while she was giving Perry a musty dog.

Mr. Chad frequently asks his employees to give him a musty dog.

Terry could not resist asking for a musty dog after cutting the grass.

William: Hey Brandi. I think we should try something new today.
Brandi: Like what?

William: Give me a musty dog! Now!

Brandi: But William, you have so much hair all around your ass and on your taint, it will be like eating a hay bale. Consider shaving that monkey ass of yours and then I will give you the best musty dog!
William: Okay, I will do as you say. I may be whipped, but I'm so horny right now.

Mr. Wardrip frequently gets a musty dog on Sunday afternoons.

(also frequently referred to as "getting a Wathen"
by Baskin McGlory June 20, 2012