Its called scratching!!
no
could be a number of things, there are glands around the butt, usually they empty when the dog has a bowel movement, sometimes they get blocked , that is when the dog scoots on his butt across the floor, a vet can show you how to empty these glands, that is one problem, could be worms or something stuck to the butt like poop.
I think your dog may have the following , An itchy butt
pull down your pants and rub your butt along the side of the road and see how many scoots it take to reach a mile
he may have worms. or maybe its just an itch. but if he continuously does it. see a vet or get worm killer/ prevention.
across the chest or across the butt
Butt
butt
You can find a auto cad floor plan up ur butt
butt crack.
You use your hand or rub it on the floor to scratch it. Maybe sit on some stairs and scoot down them on your butt.
The goat will butt you out the way.Scoot your butt over a bit would you?Dropping your cigarette butt on the floor is littering, which is an offence that will get you fined.