Take a look at it, is it clean? wash it off, remove any dried feces, some longer haired dogs get this and need washed there from time to time. you dog could have had diarehha you may not have know it and now some of it has dried up there, I know it sounds awful but you need to take a look.
Fleas!!!! yes fleas could definatly be a cause but as i myself make a living training and showing dogs i could also suggest to you, dry skin, matted hair, ticks, dry poop, stickers, all stuff that simply would not happen if you took care of the dog try giving him a warm bath check for any thing that can be extracted and then give him a flea/tick bath and rub some warm baby oil on him to prevent dry skin if you need farther grooming advice just ask.
The dog could have fleas or need its anal glands expressed.
He might have an infection.Consult a vet.
or Is just cleaning it........
He may be having a problem with fleas, other parasites, or dry skin. Check with his vet.
Because biting their tails and turning in circles is entertainment to them I guess.
some do mostly when they have fleas though
They are cleaning it because they just pooped in your house so go clean up
it might be because it has fleas or ticks
chew your butt
Yes, A dog could vomet after eating a chew toy
Get the dog some good chew toys. Dogs need to chew.
rice
It's dog's butt.
You will poison
A Bone
A Bone
No, but chow is.
It's awful to imagine it but if a dog is in enough pain and distress it might be driven to chew off a toe.
Means he wants some
No They Will Die.