[Tread]

I don't have a clear prove, but there are indications that it is a (very well done) fake.

The penis and scrotum have slightly surface shadows on the left side (viewer), and the girl is extensive lighted (the light source is a bit above and central from the camera). The cock shadow on the wavy shirt doesn't bend. The behind/underneath cock/scrotum shadow seems not to be 100% correct.
The penis proportion is unusual big.
Someone signed the pic with Willy (I don't think it's her artist name).
She has a clean shaved penis/scrotum, but public hair above and underneath it. (If you look close, she even has hair at her alar). Implausible to me, why not shave the ass too?
There seems to be a small cross-over, retouching and tiny transparency visible at her left thigh to scrotum/penis (right from watcher). Maybe need some experience to see.