Lyric discussion by InoMan 

It is definitely about sex:

"Something in you, it jitters like a moth", they are probably lying on top of each other and he can feel her heart beating fast.

"And I see that your arms are out to God", her hands are raised up in the air

"And oh, they kill you when they talk It makes a mountain peak seem little when it's not", it killers her when she sees people talking about them being together, it's making a mountain out of a mole hill.

"Your incubator is so tight Your incubator is so tight I've been born before, I'm pretty used to it Brain-dead is always all there is", and this is clearly talking about her vagina and how he's used to seeing them because he saw one when he was born. I've heard that when a man orgasms his brain becomes clear of thoughts for a few moments, hence braindead.

Anyway, the rest of the song follows this pattern.

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