No coordinates unfortunately, but you'll easily find it. It's on "Dilgry Circle" in the Barrington Tops National Park.
That's a loop road of about 14kms apparently, so if you miss it the first time round - it's well enough signposted - the worst case scenario would be going around again.
If you google search it up, use "The Rock" rather than "Cock Rock" as most respectable sites refer to it by the more polite name.

I rushed the shots and blew out the sky, and didn't really have time to try exposure bracketing or the like, so haven't shared any photos of it on here as I wasn't happy with the photos. If you thought this one was funny, you should see the one where I held my hand out in front of the camera so that I've got my hand around the shaft.