It's a piece of cake. I simply rub the oil on the area(s) to be heated and apply heat directly to the wood. As the oil heats up and soaks in, I apply more. The oil will help prevent scorching (although the wood may still discolor and darken). It also helps to hold the heat in longer and help it penetrate the wood more deeply. I've not have a problem with any finish not adhering properly after using olive oil. You'll generally sand some of it away. I also rub it down with acetone before any gluing or finishing, which helps remove both the olive oil and excess natural oil in the wood.
If you find that you need to heat an area again, no problem. Add more olive oil and heat it up. It's a very low maintenance and hassle-free procedure. Plus, it smells like a gourmet pizza!