You don't even really need to tuck the silicon back in, just gently work the edge of the H plastic by pushing up and out on it (as if you were going to take the plastic off) and the silicon will disappear back under the case.
My NEO Touch was loose. It creaked in my hand a lot, and when I squeezed it you could actually see completely through a gap between the I plastic and the H plastic (from a profile perspective). This defect, combined with the difficulty of getting the silicon skin back under the case, led to the silicon case repeatedly coming out of holes for the volume rocker and sleep button. I sent them an email, they asked for pictures and my order number and address. Once I provided that, they told me to keep the case and just buy another one, and they refunded all of my money, including shipping. I'm not using a case right now, just the screen protector that I had applied and the little dock plug that came with the Neo. I'm trying to decide what to do, because I'm starting to agree with iLounge--the Neo Touch is one sweet, protective case, but it's just a little too ambitious for any consistency in their manufacturing process.