A build up of stomach pressure leads to pain and the feeling of needing to poop. When you arrive in the bathroom, the pain peaks but you realize that there is no poop to be had. You break out in a cold sweat from the pain and just fart until the pressure subsides. Normally one incidence is enough to relieve all pressure, but it has been speculated that several Fart & Sweats may be neccessary in a severe case.
After a day of not eating any food, we went to a bar to have some drinks around 4:00 p.m. About 2 pitchers in pressure started building accomanied with pain. The distinct feeling of having to poop washed over me and I rushed off to the bathroom, hoping that said poop would relieve the pain/pressure. 15-20 highly embarassing minutes in a doorless bar bathroom stall later I emerged sweaty and without having pooped, but feeling much better.