One thing to remember about laptops is that they're not actually meant to sit on your lap. There are fans underneath that get blocked whenever they're pressed against the human body causing the machine to overheat. It's much better to have it on a hard surface when working. Have you tried one of those lap tables? That way you can still hold your hands in the proper position without bruising?

For me, I generally have my Surface on a table or desk or I have a lap table that I use when I'm sitting on the couch.