I have started the foundation work for the Object Guard with both my boys, though my question only pertains to one of them.
Basic Overview of the Exercise:
The dog must guard a basket from the decoy's 3 attempts to steal/displace the basket. Dog should bite the decoy as close to the basket as you can keep your dog and must then release the decoy when he takes a step back. Dog must return to the basket after outing off of the decoy and go back into a guard. Handler is not present.
My plan is to teach the OG by starting with a regular place command. The foundation is going to be built using clicker training. Right now I am using part of a cereal box for this exercise.
Anyway, my question pertains to Cairo. He is a very mouth oriented dog and much of the time that he goes to this cardboard piece he puts his mouth on it, bites it, moves it, etc. I stopped the session because I wasn't 100% sure how I should treat this. Should I click/reward for him mouthing the place marker now and extinguish that particular behavior later? That way he would be getting click/reward with any part of him touching the cardboard. OR should I only click/reward for non-destructive ways of touching the box? If I approach it in the latter method, should I go ahead and give him a negative marker for mouthing the place marker?
My concern is that in a trial he may get stressed, over-excited, etc and decide to decimate the basket. I am wondering if the click/reward for him putting his mouth on the place marker now will make that more likely to be a default behavior?
I am interested to hear y'all's thoughts. Thanks.

). I would probably try to stop the mouthing behavior from the beginning, but I wouldn't use a negative marker. I generally teach place by shaping it, so I'd just not click for mouthing, and go back to clicking more for earlier steps like moving towards the mat, and click before the dog starts to mouth, even if it's clicking as the dog's mouth is moving towards the mat. It usually only takes a few earlier clicks for the dog to realize that he doesn't have to mouth the mat and that mouthing won't get clicked. Once the mouthing decreases, then I'd build in other criteria (duration, distance, distractions, etc).