The person who, when drunk, causes or creates drama for everyone around them. This person typically claims no memory of their drunken behavior the next day.
Eric "Are you partying with Jemye tonight?"
Ann Marie "Hells no! That girl is a drama drunk! She had a nervous breakdown last time she got drunk. I had to babysit her all night while she cried about her childhood. This isn't therapy!"
The act of being so drunk that you can not remember the part of the night where you punched your friend in the face, took off your shirt and went to sleep in the bathtub.
I was just having a couple drinks, next thing I know I'm waking up shirtless in the tub. I was totally bathtub drunk.