It is called the swedish fire log. pour and soak for a few days or weeks. then when you need it start it on fire and you have a fire log that last for hours. we did this in the snow when we had parties or people over to keep warm.
To roll out your Psoas, lie face down on the ground with a ball on some books. Place the ball on the books in your abs above your hip to one side of your belly button. Relax over the ball and lie face down on the ground.