For man, being a slave to a pretty girl usually means he needs to prove himself. After all it's not like girls like Parker don't have a lineup of men that want to grovel at her feet. To prove their worth typically involves him suffering for her, demonstrating that he wants to be her slave so badly that he will happily hurt for her. And so it goes for this slave today, he desperately wants to be owned by Parker so he needs to prove his worth to be granted permission to grovel at her feet.