I’ve only seen still images so far but it appears to be a terrier of some sort. In the images I’ve seen he also appears to be performing oral sex on the terrier. Aside from the situation in general, I find this to be odd since I do not believe that a terrier would (a) understand what being licked out was (b) enjoy being licked out.
It’s probably like that episode of South Oark where the older kids tricked the boys into thinking they could milk their dogs