Lyric discussion by EatAtJoes121 

Cover art for Lightness lyrics by Death Cab for Cutie

The song is kind of contradictory to me. I think (of course) that the hook is about lust. (I took 'ivory lines lead' to mean the skin exposed fromthe torn dress) . The second verse is the opposite however. Her heart wants to love him but she fights her feelings with her brain. And 'you shouldn't think what you are feeling' means that you should go with your heart.