Also known as "FFT." Have you ever noticed that people tend to work out on Thursdays? Or maybe you yourself tend to work out on Thursdays. This phenomenon occurs because it's Fucking Fit Thursday. Every Thursday, your body sends out kinesthetic neurons to your muscles. Your muscles then begin to ache and twitch. This is because your muscles are craving the exercise. Once you begin to work out, you'll realize that your muscles are beginning to calm down and that your endorphines are at their peak. You will be able to work out for hours, but remember this only occurs on Thursdays.

A casual invitation / threat used by an individual that is not afraid of fucking someone up.