A day on which you are allowed to break your diet, as complete abstinence is impossible for most people. It also provides a reward for the sticking to your nutrition plan over the rest of the week. The "cheat" can be small (e.g. a chocolate muffin with lunch), large (e.g. a fast food meal), or systemic (e.g. Full Fat Friday).
A disease that infects both men and women, but is more common in 18-30 year old males. The symptoms include, not answering phone calls, disapearing for months at a time, loss of testosterone (or estrogen), crying while masturbating, no longer partying, and the loss of the ability to maintain arousal. The only known cure is to mercilessly ridicule the infected individual about loss of balls.
A person who has a low tolerance for alcohol and becomes intoxicated quickly after relatively few drinks.
The expression originates from the "traditional" dating scene where men pay the bill for the evening, including for the woman's drinks. The intent is that little money is needed for them to either have had their fill for the evening, or to be drunk enough that sex is likely to follow.
In modern times, the term is applied almost equally to men and women regardless of orientation.
Sara : Oh Jake you cock is so strong! Uh! Uh! Uh! Uh! Uh!
Jake : Yeah and your pussy is so soft! Ahhh! Ahhh! Ahhh!
Kiersten : Hey Jake I brought us some goodies since it's Cheat Day! OH MY GODWHAT THE FUCK ARE YOU DOING!
Jake : You said Sunday was Cheat Day so I thought we could fuck other people!
Kiersten : You DUMBASS we can cheat on our diet not each other GOD DAMNT!
Sara : Oh Jake I'm CUMMING I'm CUMMING!
Jake : Ohhh! It feels so good in there!
Kiersten : JAKE GET YOUR DICK OUT OF HER NOW!
Jake : But it's Cheat Day!
Kiersten : That's It today is BEAT DAY cause I'm gonna beat the shit out of you two!