A Maturity Wanker is an insincere writer; insincere in a special way.
I recently read a book of stories by Milan Kundera. Although I enjoyed them enormously, if I was a (healthy) woman I would have been extremely annoyed by the sexual politics of the writing. All the stories were fundamentally based on the objectification of females.
Although I disapprove rationally of such an outlook, I like Kundera's honesty in this regard. He's utterly sincere about the cynicism of his own psychology, which, if we are going to be completely candid, is also the psychology of most males....
There are too many insincere writers out there who constantly glance over their shoulders to see who is behind them and tailor their prose to please that audience. "Better make myself look nice in front of women!" "Better make myself look compassionate and reasonable!" "Better do something to attract the pink pound and the socialists!"
Such writers are maturity wankers.
True sincerity is about accepting what you are; being open about your perfectly natural dark, aggressive and selfish desires (which are really only promptings of the Id, which we all have) and never pretending you don't have them. Morality consists in choosing reason over urge, not in pretending not to have the urge in the first place.
Writers who pretend not to have the urge are maturity wankers. A great many modern writers are maturity wankers. They are, in fact, in the majority.
The prime aim of a male maturity wanker is to make himself look good. To make himself appear reasonable, nice, tolerant, fair, sagacious and ethical, and he does this for a specific and acqusitive purpose: to be approved of, to make himself liked by women in order to get them into bed more easily. Because the fact is that reason, niceness, tolerance, fairness, sagacity and ethics are alien to the human condition on anything other than a tactical level. These are tools of social acceptance and communal interaction used to make our lives easier. They are not products of our deep psychology, of our true drives.
A male maturity wanker is a writer who has learned that if he says "I want to fuck women!" his chances of fucking women will be diminished; but that if he says "I think that women should be treated as human beings and not as sexual objects!" his chances of fucking women are vastly increased. He has learned a technique.
I prefer writers who don't pretend to be nice but who are truthful instead, no matter how much damage they risk to their reputations as a result.