Teaching 'gentle' at the beginning of your dog's clicker training journey will make things much more pleasant for everyone! So lets address the issue of your dog taking the treats gently. It's no fun to have your fingers gnawed when presenting a treat so teaching being gentle in the beginning will really pay off long term. This is especially important if you have children and would like them to be involved in the training process.
So to teach 'gentle' you just need some of your dog's normal kibble.
Start with this quick training game.
Face your dog with a small treat, hidden inside a closed fist.
Ignore any pawing or mouthing at skin to get the hidden item.
As soon as you get a lick from the tongue or a nose poke- click and reward.
Repeat the click and reward with each gentle touch
This teaches your dog that though pawing and biting never work, soft touches will. Your hands will be thankful for your efforts