Generally speaking I inject in one of two places depending on what I have planned for the day ahead. If I'm not doing a lot in terms of exercise then I inject in my legs, as the absorption rate is higher. If I'm going to the gym or on a bike ride (as I do 3 times a week, covering 30 miles a week), I inject in my belly as the absorption rate is lower. There are occasions where I break these two rules, such as when I need my BG levels to drop quicker. I've never been able to inject in my arms as I am unable to pinch the skin and inject with one hand, as for the buttocks I can say I've had the need to, as I also rotate between legs and area on my belly.