If you want your dog to leave a disc alone, simply pick it up without triggering any prey drive.
A super slow and steady pick up of the disc is a great way to clue a high drive dog into the idea that it’s not that fun to hit these sluggish, nearly dead, targets.
Dogs often are conditioned to attack the disc as the handler is picking it up. The handler moves super slow and methodical, almost daring the dog to steal it, or building up lots of suspense and drama, only to finish the move with a quick snatch of the toy.
This essentially becomes a stalking drill for the dog.
Just move super slow and steady, don’t respond to the dog’s actions. Move slow, but continue picking the disc up — don’t fight or anything, if the dog steals the disc let it fall and do nothing for a moment. Perhaps move to another disc.
Keep it slow, steady, and super boring.