Where does the phrase "Git-R-Dun" ("Get-R-Done") come from?  It is
being used casually and more frequently.  Recently, my friends and I
started to debate the origin; specifically, whether 'R' refers to 'her'
and, if so, whether 'her' refers to a woman or an "effeminate" object
(e.g. sailboat, car, ...).  Does the phrase refer to women as sex
objects or is it simply a fun phrase synonymous with 'get it done'? 
My
friends and I agree that it comes from a "Redneck" TV show, but we
don't agree on the meaning of the phrase.

The phrase has come to be associated with "Larry the Cable Guy," but
he didn't invent it.

http://www.larrythecableguy.com

I am a native of Oklahoma, and I've heard "git 'er done" and variants
of the phrase ever since I was a youngster. In my neck of the woods,
it just means "get the job done." Referring to a task in the feminine
gender isn't uncommon among us Okies and our Arkie brethren (and
sistren). When I was a kid in the '50s, I remember watching some men
building a fence in my neighborhood. Just about every portion of the
job was referred to as if it were a woman. "Come on, hold 'er straight
and I'll nail 'er down" may sound sexual, but it was just everyday job
talk.