It is choking when the water is sucked into the trachea and into the lungs. If you only put some water in a person's nose without letting him inhale it, he will not choke. Elephants are a case in point. If you look carefully, you will find that when drinking water, the elephant sucks some water through its nose (not into its lungs), then raises its head and puts the water from its nose into its mouth to drink. In the process, it only uses the nose as a tool to absorb water, not as an organ to drink water.
 The point to be demonstrated in this paragraph is that water sucks into the trachea and lungs, it chokes.