My bottom's what?

Last night I went to bed far too late after a long day and a long week.  I was tired and down.  As I lay in bed trying to unwind, I tried to think of a lullaby ... something to soothe myself to sleep. The first song to pop into my head Annie's "Tomorrow"

But wait, I hate that song.  First of all, tomorrow never comes.  For once it does, it's TODAY, and tomorrow, with it's promised sun, is STILL another day away.  And besides, tomorrow is just as busy ... I have the "to do list" to prove it.  

Not only that, the song has stupid words.  Case in point:  "Tomorrow, tomorrow, bet your bottom's dollar that tomorrow ..."  My bottom's dollar?  I've wondered my whole life what a bottom's dollar was.  But as I lay in bed last night, imagining typing this blog, I realize it's not my BOTTOM'S dollar - it's my BOTTOM DOLLAR, as in my last dollar, everything I own, a sure bet.  

HA!  For 30 some odd years I've hated that song because I never knew what my bottom's dollar was or why Annie was betting it on tomorrow's sun.