Check it out. When you are trying to cork hard(not just like drop your shoulder), you first need to be able to throw the rotation clean. I recommend 5's, since it's easy to visualize this trick. I find it super hard to cork without carving into a lip, but if you can, i guess you don't need to read this.
To cork, carve leftside, spin leftside, drop that shoulder, and as soon as you come around from your first 270 or so, find that landing and don't lose it, and you should come naturally back on axis. SHOULD is the key word here, because sometimes your body won't and you have to adjust your legs, which is why it's important to never lose that landing.