His skill is basically just urethra insertion but with sword. Imagine him trying to have sex but the one inserted is the sword handle. This is also the worst power to have if you're a public figure lmao can't have a dangling dick in front of the people.
On another note, what if the dick is...
I totally forgot but did MC never get into any life threatening situations? All that time and he's still has that pacifist, no-killing mentality and I don't think him being a teenager (how old is both of them anyway?) is a good enough reason.