It's when a guy is deciding whether or not he should fuck a questionable-looking girl...first, he jacks off, and after he cums, if he still wants to fuck the girl, he should--the loss of the horniness and clouded judgment immediately after orgasm is the "moment of clarity".

The moment when a person realises (realistically) how breathtakingly/completely drunk he/she really is.

Usually occurs when out partying/clubbing, and most commonly when using the toilet, as the environment is mostly devoid of any stimulation and allows the person in question to self-reflect and fully comprehend how drunk they really are. May also happen when sitting alone for a period of time.

Note for guys: a moment of clarity may be unlikely if using a urinal/trough due to fight or flight response which may distract you from any quiet self-reflection.

This "moment of clarity" is usually accompanied by other strange thoughts including: admiration of the design of the toilet, wall paper, graffiti. Also looking at yourself in the mirror and realizing u look like drunk but you don't care because the feeling of accomplishment for being so drunk and knowing it overrides that.