What does it mean when your dog scoots on its but and lays downin between your legs?

He wants your helps with an uncomfortable problem with impacted anal glands, most likely. They are located left and right of the dog's anus, and in some dogs the fluid buildup in them needs to be gently squeezed out into something like a gauze pad. The dog is NOT happy about this problem!

Perhaps a veterinarian can show you how it's done.