The guncky build-up underneath the flap of skin on an un-cercumcized cock.
Girl: That boy got duct butter in my vagina.
by Rickifer July 03, 2006
Usually found to be having a fetid, putrid odor, not unlike that of James Swingline. Usually found to have the texture of tapioca or hemmeroid cream. Origins are in Lakeland, Florida.
Much to his dismay, he found ductbutter in his anus. Consequently, this caused his girlfriend's bad breath.
by JT Cernero January 06, 2005