This one and 'Are You Ten Years Ago' are so weird songs for me, like it's not Tegan and Sara stuff. There is a video of an in-store performance of this song, Sara messes up a few times, but doesn't give up. Model through it!
Someone pointed out, Sara's mentioned this song referring to problems with drug use & wanting to ask for help but struggling. Like, 'I really think I need help here, but I don't know how to ask, so I'm hoping you can figure it out/notice something is wrong, without me actually having to say anything.' I figured that "like O, like H" was simply an exclamation "OH" of sudden comprehension. Gut instinct, as it were.
@GhostFreak6: I read that this song is about how sara experimented with drugs when she was a teenager. She wanted to tell her mom that it was beginning to become a problem, but she was afraid to. And I think the "S.O.S. to my mother, take the hinges off the door" and "Sugar, spell it out" parts sort of refer to that. I have no clue about the "Like O, like h" bit though.