the dirty duggan is a sexual act in which the male shits on the female's (or other guy if you're gay) ass and then rubs it around with his penis. after this has been completed, the male has anal sex with the partner and ejaculates on their ass. he then rubs it around again. the dirty duggan has been completed.
Someone who goes out and tries to wrangle as much random snooch as possibleand then shove his wang into her yo yo smuggler just days later without any thought of his own well being.
This is when you have a bald man, and his lady/ male companion which ever is perferable takes a shit on the top of the bald mans head to make a "Toupe".