It seems to me that a pious male teenager or adult should be satisfied and patient with the feeling he gets from nocturnal emissions (wet dreams) which are normal and not sinful. If he wants this sexual pleasure more frequently then he should marry. I'm not sure what's the average per month of a wet dream for a normal teenager. It becomes more of a problem if he finds out about masturbation and then starts doing that which is sinful and he can then get that feeling many times in the day rather than say every 2 weeks via a wet dream.
How does fasting reduce sexual passion if he doesn't masturbate or know what it is and doesn't look at females in whatever form in the first place as he knows these are sinful?