I have the new tool for "whacking" your quilts. It does work. After buying it I thought any rubber mallet with a flat end would have worked and probably would have been cheaper.
Just steam the spot you want to whack and then WHAM, it's flat. I put the pieces on a cutting board (I sew in my kitchen table and don't want to damage that) and it works fabulously. Not sure how, but it is flat when I get done whacking it.
ps: great stress reliever :)