Squirting lemon juice into someone’s mouth to get them to salivate is also not verbal behavior because the listener’s action (salivation), although an example of mediated reinforcement, is not specifically trained in order to reinforce speakers.
Behavior that has the following features:
It is established and maintained by reinforcement
The reinforcement is mediated by another person
The other person’s action that results in reinforcement must have been specifically trained in order to reinforce speakers