A: The idea is to put it into the draw deck in such a way that you don’t know where it is, so that you wouldn’t know who might draw it. Exactly one card from the top would certainly not count. If the draw deck is very thin, you might need to deliberately shuffle or mix up the cards so that you don’t know where it ends up.
If you want to get technical, you could shuffle it in to the draw deck no matter what size. Yes, it absolutely MIGHT end up second from the top… but you wouldn’t know that’s where it is, and that’s the point.