I read some of the novel a long while ago and the manga does a bad job explaining it.
I think his excess magic is what causes his libido. And in times of peace it has no where to go so it builds. Then the libido fucks up his concentration and he'll explode if he doesn't err...explode in other ways.
I think
It's been a while. ╮(￣▽￣)╭
I don't think it's like that.... he has strong libido and his strong magic gives him more energy making his libido stronger... or at least that's what I got out of it.. but I could be completely wrong...
Then why doesn't he masterbate like all men do?????? He's gonna get cancer if he doesn't do that lol
I don't think that's how you get cancer
So basically magic is stored in the dick and instead of exhausting the excess by working out or something he just fucks off that magic or else he dies?