The concept here is that Ruff is sleeping against a dragon friend of his and is having a pleasant dream about entering the dragon's mouth. But this dragon has the ability to actually (physically?) enter the dreams of others.
It may seem confusing, but to quote Ruff; I was thinking maybe Ruff could have like a dream/sleep bubble coming out of his head, with the dragon sticking his head into the dream bubble, letting dream-Ruff look and/or crawl into his muzzle. (Because, of course, a vore dream for Ruff is a very good dream indeed! ..and the dragon can do that, cuz he's a dream-dragon, or whatever, so he can exist in the physical world as well as the dream world)
As usual it looks nowhere near as good as the original after being scanned in but luckily Ruff can see just how much better it looks when I mail it to him!
Both characters are his.
Art is mine.
Link
holodrom
Both the concept and execution of this are fantastic. <3