Two problems !

I have 2 year old black short hair chihuaha. He doesn't like other dogs, when he sees or smell a dog he barks and barks and throws a fit. Should I take him to a training school or is he too old.

Rocky, my dog, is not yet neutered and recently he has been licking his rear end constantly - is there a reason why ? or should i take him to the vet.

I have never seen him do this before !

Heya!

Two years old is not old for a chihuahua... Or most any dog, for that matter. It doesn't matter how old they are, really, any dog can be trained. Chihuahuas are well known for having social problems if not trained to be a people puppy when young, but that's fixed with enough patience.

Are you keeping Rocky intact to breed? If not, I'd agree with MGM and get him neutered. If he's dragging, he may have worms that definitely need to be checked out. Not to worry though, medication is available that will make him right as rain.

Good luck! Keep us (or at least me :P) updated!