I just use it on my arms. I will say however, that if you have a willing participant to help you with it, it makes life a lot easier. You would die laughing if you could see me doing it on my own, I have even resorted to placing the needle inserter into a vice in the garage to help me pull it out. But it's definitely worth the hassle in the arms as I find that it's more out of the way and so far I haven't had any failures over the 4months I've been using them.