... it [masturbation] too often leads to grievous sin, even to that sin against nature, homosexuality. For, done in private, it evolves often into mutual masturbation - practiced with another person of the same sex - and thence into total homosexuality.
To be mediocre, when only application and diligence would have netted superiority, is an error akin to sin.
Sin is the result of deep and unmet needs.