How are you supposed to use stretch mark preventing belly er? It's hard as a rock! ?

Knowing my desire to do anything I can to help ward off the inevitable stretch marks pregnancy will bring, a family member gave me some Palmer's Belly er. I tried using it the other day tho...and I'm confused! This tub contains a substance that is hard as a rock, and I can't get more than a minor film from it onto my fingertips. Is it supposed to be scd off? Warmed? What is the deal?