Verb: The act of excreting shit and gas while farting!
The origin of the word "shart" is credited to L. Crowley (1986) after observing her brother excrete a little extra something along with his explosive gas after after a night of endulgence at the turkey testical festival.
Cat 1) Wet Sensation
Cat 2) Wet Underwear
Cat 3) Soak thru to inside of pants
Cat 4) Soak thru pants (Visible to general public)
Cat 5) Runs down to socks. (Oh my god, run for your life)
Anything of Category 4 or higher require showers. The lesser categories can be dealt with using alternative cleansing methods.