For me the real evil of masturbation would be that…  it sends the man back into the prison of himself, there to keep a harem of imaginary brides.  And this harem, once admitted, works against his ever getting out and really uniting with a real woman.  

For the harem is always accessible, always subservient (prepared to obey,) calls for no sacrifices or adjustments and can be endowed (provide) him with erotic and psychological (related to the mental and emotional state of a person) attractions which no woman can rival.

Among those shadowy brides he is always adored, always the perfect lover: no demand is made on his unselfishness, no mortification (the action of bringing under control one’s desires) ever imposed on his vanity.

In the end, they become merely the medium through which he increasingly adores himself…

After all, almost the main work of life is to come out of our selves, out of the little dark prison we are all born in.

Masturbation is to be avoided as all things are to be avoided which retard this process. 

The danger is that of coming to love the prison.

C.S. Lewis

Our Sex Drive is intended to bring us out of ourselves and into a relationship!