Two areas of doubt:
1) Is it real? Not sure, but very doubtful. Particularly when he's shooting from behind, through the legs, when he's about to come into that mug ... the head and the last part of the shaft just somehow look artificial to me.
2) Is it 15 inches? Definitely not. It goes just to the knees. A 15-inch dick, on almost anyone, would hang past the knees. This is probably more like a 12-incher.
If it's real, it's more for the circus than the bedroom.
For me, at any rate, it's astonishing if it's real, but past those first three seconds of stupefaction, it's not only not erotic, but not even particularly interesting.
Just mho.