Brown tint of fecal matter found on the tip of your finger after itching or playing with your anus. This is most commonly observed and then sniffed.
After a short jog, Jimmy reached down his sweats and scratched his anus. When he pulled his hand back up, he had a rusty finger, then sniffed it.
by Robbbbbbbbbbbbbb October 31, 2008
The art of fingering your butthole and then using your rusty finger to brush someones teeth. - Jim Williams
by loverofallthingsrusty August 14, 2015
Like a rusty trombone, but somewhat straighter. Performing anilingus on your woman whilst diddling her vaginal canal. Classy move, and lets her know hepatitis ain't no thing.
by TrevtrevO May 29, 2010