I tired this a couple times yesterday. I know your supposed to drop your shoulder, but when I did I just did a lincoln. And I am carving off HARD, but my three is not corked even a lil.
Start off doing cork 1 bellyflops then once youve recovered from a few of those then you can just take it to the three sixty and huck a lil harder and you will be on your feet like a magical pegasus
just carve your 3's all day errday and dont worry about trying to get corked. Once you have a nice carved 3 you just keep doing them and just start looking at the landing through your legs almost. By that time you will be feeling the cork a bit and from there you just play around with it.
The best way to do them is to carve hard and pretend like your putting your skis flat against a wall behind you and suck your knees up. Basic C3's are mostly an illusion, getting truly corked takes balls.