The theory states: initially, said person, has failed to properly wipe their crack fully, thus leaving remnants of shit (dingleberries). With strenuous activity and/ or heat, sweat develops within the ass crack. This sweat mixes with the now encrusted and dried fecal matter, bringing it back to life, creating a noxious fume- comparable to shitting your pants.
Proposed in 2006.
Shitinderpal: 'Yeh geez, me too. I smell it all the time in this lesson, it's probably (insert name here), 'cus he's so fat- he properly can't wipe his arse properly!'
Turdepreet: 'Oh yeah, that's a good point, that ties in nicely with the 'crack sweat' theorem (2006). That explains it!'
Shitinderpal: 'Oi (insert name here) you fat twat, go wipe your bumhole son, you need some bleach in there, smells like hardcore shit!'