Jenny is one of those girls who, simply put, like to be put in her place and given a sound spanking. Sometimes you just can't over think things. She simply enjoys a man training her to be the best sex toy she can be.
It's certainly not for every woman but rest assured she's not alone.
It's very therapeutic for Jenny to be spanked into submission until she cries and then ordered to swallow. I think it is a kind of release from total responsibility. She wants to, in a way, be naughty and punished and nasty and slutty but not be in control of that. She wants to surrender that to a man and by doing that she relinquishes responsibility for actions she wants to do but instead is being made to do. Does that make sense?