shit nails 

A term used to describe an angry or extremely unpleasant surprise in reaction to information or a situation. Akin to "shitting a brick," the term derives its meaning from the horrific experience that "shitting nails" would be, and thus a person suffering through it would naturally be in a pissy mood.

"Evelyn shit nails when I told her I didn't really get a vasectomy."

shit nails by Pimpsta G February 26, 2008

shitnail

N. This describes when one does not wipe (in going to the bathroom) properly, and thus infestations of what was to be wiped are now pushed under the poor sap’s fingernail(s). (This term was begun by Artie Lange of the Howard Stern Show.)

“Yo Bill what’s that under your fingernail? You stupid ass, can’t you wipe yourself? Now you’ve got shitnail.”

shitnail by Sigge December 22, 2008

ShitRails 

The rails in the handicapped bathroom stall. These rails are extremely useful when taking a massive shit. They help with leverage.

Man I had to use them shitrails while taking a shit.

ShitRails by Acid Kool aid July 22, 2016

ShitNail

After fingering your partners butthole, you now have shit under your finernails.

Hey get your shitnail away from me you butthole fingerer.

ShitNail by Danielle Shaw February 25, 2008