Being in the tank can be most closely described as sulking.
It is more accurately represented when a person usually of little moral character, strength or validity is upset, sad or unable to find joy because of something meaningless, trivial, relevant only to themselves or just plain stupid that has occurred that has caused them to sulk.
The resulting behavior from "being in the tank" usually manifests itself as inability to function even to perform the simplest of tasks, a concerted effort on the part of the sufferer to bring everyone around them down and a widespread lack of passion and enthusiasm.
Terry missed a few shots in practice and immediately was in the tank about it, because of this the whole team chemistry was fucked up. Get out of the tank Terry! Your ruining it for all of us! tanked.
Mary was acting way out of line last night so I shouted at her and put her in the tank, she deserved it. I tanked her.
I was trying to tank Hugo last over his poor ability to speak to women. i love tanking people.