Shillack: (Verb) to chill in slacks (eg. jeans, khakis etc…) while watching TV and eating cereal.
Ex. 1: We were shillackin in the mornin' before class watching Sportscenter and eating Captain Crunch.
Someone who takes large objects up the pooper then sucks them clean. Then meets up with a Diehl
for some afternoon delight that involves whips, a Sigfreid and Roy DVD, three gerbles, his mothers undies, taco meat, a nine iron and 3 pills of valium which he uses as a supository for euphoric effects around the anus area. A Shillack has never gotten a boner from a girl... ever. The only thing that gets a shillack off are Chippendale dancers and pictures of Lance Bass.
Last time I invited a shillack over, my valium perscription was missing and he was wearing his moms panties on his head.