Dogs sniff other dogs butts. They communicate in such a fashion, however odd it may seem to us.
One day in the park, before I had a chance to stop him, my dog stuck his cold wet nose up the back of a womans shorts. Yikes !!
She rose up straight on the balls of her feet, and shouted, *whoooooo* !!
Fortunately, she was a dog lover. I profusely apologized, and she smiled broadly and said, *Thats okay, I have dogs too*.