I don't poke at them. I either give them a wide berth or shoot them.
I poked at a common water snake while tubing a pond once with my rod. He was about 4' long.
Next thing that I knew, he was coming in the tube with me. Got him behind the head and swam to the bank letting it go.
Since found out that if one is coming for you just gently push it away with the rod tip. Don't slap at it. They will go around you and move on, while giving you time to get the .38 derringer out of the tube pocket to shoot it.