I was trying to use a diamond impression mat (the hard plastic kind) to create a quilted effect on a cake, but the icing kept sticking to the mat and pulling off the cake. I used Sugarshack's icing recipe and let it crust for over an hour, but every time I tried to use the impression mat, it pulled the icing off. Any idea what I might be doing wrong? Could it be the weather causing that to happen (it was raining)?

Did you try dusting the mat with a little cornstarh or ps? That should keep it from sticking.