Yes, “how low” might refer to a blow job, and alternatively it could refer to a low between taking heroin. But it has so many possible meanings — depression, for example. And since “hello” comes before it, you could even take it to mean the depression, emptiness and ugliness inherent in a teen world where teens are forced to be polite to the older generation, even though they don’t want to — when teens are forced to be something they’re not.
I think, in general, this song is just about teen life. MrSkaPunk is probably right; Kurt didn’t put much effort into the meaning of the lyrics, but what he wrote down can nonetheless be analyzed. And I think that its best taken as a multitude of emotions, actions, diversity (mulatto, albino), acceptance, rejection, and the ups and downs of teen life.
My InterpretationLoad up on guns, bring your friends It’s fun to lose and to pretend She’s over-bored and self-assured Oh no, I know a dirty word