Reaming a dude from behind (doggy-style) and then rimming his asshole with your finger with which you run it (fecal matter and all) under his nose as to make a moustache with. Similar to the Dirty Sanchez, except strictly male related.
My boyfriend Leonard was pissed, so I gave him a Dirty Ferg last night.
by DirtyFerg June 27, 2010
Get the Dirty Ferg mug.