I'd also like to know his name. The watermark in the lower left-hand corner reads "muscru". At first I thought this was the name of the studio that produced the scene from which this gif was taken (it doesn't look like an amateur production to me), but I was wrong. According to a forum I found, it's the handle of someone who once maintained a catalogue of gifs on tumblr.
Here is a link to the forum:
Muscru videos.
And here is a link to a MyVidster account/channel that appears to have been created by the same person:
muscru.
I considered skimming the videos in his collection in case one should feature the unknown model, but there are more than 260 pages worth. Ain't nobody got time for that.