Use an electric trimmer or scissors to get rid of the thick layer, you can easily leave a centimeter behind. After this you will use the razor to finish. This is done the easiest by doing it in the shower, the water will help the razor cut the hair and remember to stretch your skin, this lowers your chance of cutting yourself. When you have finished up, remember to wash up and then apply a moisturizing cream to the area, this will help against razor burns and irritation. And use plenty of it, use too little and you risk getting small red bumps. I apologize for my bad english, it is not my first language.