Verb: is similar to a T Bag
however, a Steam Bag is the act of placing ones testicles over the eyes of another person and then farting in that persons mouth.
a. an unconscious, drunk guy.
b. an unconscious, drunk chick.
The term Steam Bag originates from the Delta Fu Gamma - Phoenix, AZ chapter.
Dude, Nick passed out drunk last night with his mouth wide open so, I gave him a Steam Bag!