Punishment is used in training to change behavior.  It is a consequence the dog wishes to avoid.

Let’s use crooked sits as an example.  If your dog performs a crooked sit in heel position, you’ll want to make that behavior less likely next time. How might you use punishment?

You can with-hold (-) something that the dog wants like cookies, toys or praise when your dog sits crooked. You are using -P.

Or you can add (+) some sort of physical discomfort technique for the same purpose (collar correction or other physical manipulation).  Your dog won’t want you to do that in the future so straight sits become more likely (+P).  Or you can verbally harass the dog (mental force) to make him uncomfortable, so next time he will try to avoid that by sitting straight (also +P),

If it makes you feel better you can actually straighten the dog (maybe give a…