The bull is gouring the matador.
The bull ran it's horn, or horns, into the matador. Perhaps if you check Bull Fighting you can get a gest of what this practice is about. If you're referring to the picture, it has nothing to do with the matador's privates, but everything to do with the bull stabbing the man with his horn.
They can post a picture of it, but they can't look up the meaning? What a bunch of bull!
OMG! to Ol'Yeddar: It's spelled G-O-R-I-N-G; the root word is GORE. The Murphy definition is correct.
To Anonymous: Boy, are you ever right!
I, for one, will never be cowed by this line of bull!