It's a photoshopped Scene from the video "Ugoku ERO".

Proof here: http://hentaifromhell.net/videos/ugoku-ero

Tag added.

I think Ragnarok Online would be a more appropriate tag (along with Priestess).

BTW, I just watched Ugoku RO... Fucking hot as hell.

Well, I beg to differ since this certain scene is EXACTLY from this video. An additional tagt would have been more appropriate than a full replacement, imo.
But then again, to each his own. I won't argue about something minor as tags on an imageboard. Do as you please.