The goal of slave training is to teach the slave obedience, service and submission.
The education of submissive men to a perfect slave often requires some strictness in the form of punishment. Thereby a whip can be used but it can also be just slaps or painful kicks in the genitals.
A real slave never disagrees, carries out all the wishes of his mistress and is ready to be used sexually in any form by his mistress but also strangers at the request of his mistress.
A true mistress often keeps several slaves. The perfect storage place for slaves is the cage.
Examples on video for real Slave Training can be found here: Slave Training