When one has diarhea, he or she puts their hand over his or her asshole and has a bowel movement over an unsuspecting victim. This causes diarhea to shoot up the person's back and all over the victim.
Tom: What did you go to Panama for?
Alex: it's was my buddy's bachelor party and he wanted a Kentucky Slurpee before he tied the knot.
Tom: Niiice! You could cross that off the bucket list.