It means he had his penis turned inside out to make a sort of pseudo 'vagina'.
I've put vagina in inverted commas because obviously its just a hole that needs regular dilation to stay open rather than the wondrous and lovely thing a real vagina is.
It has no controlable musculature, no self cleaning or lubricating, no clitoris encompassing it etc. I imagine it's a bit mediocre compared to the real thing.