I've attached a commented capx that should do what you want. The key was to have Drag enabled always, but not actually allow movement until a variable was set after a timer.
You have to touch (or mouse left-click-hold) the sprite for one second before it will drag.
If you try to drag it before then it will just stay in the same spot.
If you drag off the sprite before the timer runs to allow drag, it will drop and you have to re-touch again if you want to drag.
Edit: Changed capx so the sprite changes colour - red = can't drag, orange = getting ready to drag, green = can drag