This is something that I've experienced, and trust me, it was probably one of the scariest driving moments of my life. The only way you're going to get up a hill is if you have enough starting momentum in the first place. If you don't have the space to do this, don't even try. I didn't have the necessary momementum (driving slowly on a curvy road), and when I started slowing down, I pressed harder on the gas. All this is going to do is spin your tires, and you're going to either get stuck or your rear is going to start slipping out.