"The drinkin' bone's connected to the party bone,
The party bone's connected to the stayin' out all night long,
And she won't think it's funny and I'll wind up all alone,
And the lonely bone's connected to the...drinkin' bone."
-Tracy Byrd, "Drinkin' Bone"
A hat, either literal or figurative, worn for a night of drinking. Physical drinking hats can have meaning in parties or drinking games, while a figurative drinking hat is more used to describe the mood.
Drinking from the Firehose is being a part of Stan the man's classes where you get so much information in a short amount of time and lots of information leaks out.
I know that this is a lot of information, so I'm just letting you know. My class is a lot like drinking from the firehose: Lots of information so drink what you can.