i had the same problem. I threw my first 3 without even really planning to do it. I was just going to 180 because I didn't think i could spin a 3 yet, but when I go to the lip, i just went for it, and landed perfectly. But after that, i started thinking about it too much. I was spinning them perfectly, but when I went to land, i was always just a little too off-axis and would land on my hip. This happened atleast 15 times before I learned how to pop before my spin. Experimentation is the key; dont give up.