I don't know about a Dynamat "liquid" product. Usually, all Dynamat is sandwiched between a paper layer and a silver / aluminum layer. The paper layer is removed and the Dynamat is typically pushed into place in trunks of cars, etc. where it's typically used. However, there are those of us that take it a step different. I remove the paper and put the silver / aluminum layer down. Then, using a craft knife, I work at scraping the tar-ish Dynamat material loose. I get a small ball of it and work it like putty. I then adhere it to the back of the Grado magnet - being careful not to cover the 2 vent holes on the magnet.
That's it! Simple to do!