The addition of an aversive to decrease the likelihood of a behavior happening in the future.
Punishment inhibits behavior, it stops it from happening or reduces the likelihood of it happening. The “Positive” part of Positive Punishment means something undesirable is added to inhibit behavior: leash pop, rolled up newspaper, aggressive pressure, verbal correction, alpha rolls, etc.
This book does not recommend Positive Punishment for dog sport training.
Positive Punishment punishes by adding something that she doesn’t like.