Does your Doodle drag his butt along the ground?

[Jane, Guinness and Murphy]

I apologize if this was already posted...I can't find anything in my search. Our six month old ALD just started rubbing his butt across the floor inside or ground if he's outside. He does this several times a day, and it's very deliberate. I'm not sure what it could mean. Are there other doodles that are also doing this?

[Karen & Lucy]

EWWWWW, that is what I thought, gross. I am going to make her an appt. at the vets tomorrow. I do look at her butt and also give her a bath and scrub scrub scrub back there. I do not always smell it, just at times. I have been thinking that is what it was coming from. Thanks