Dynamat installation

I plan on installing Dynamat in my trunk but I would like to have it stick even under heated conditions in the summer time. I heard that if not installed properly, Dynamat will unstick in the summer when the trunk lid heats up.

Is it a good idea to heat up the piece of Dynamat, before sticking it under the trunk lid, so that it's easier to mold.

Any tips regarding Dynamat would be appreciated.