My master found this bendy plastic rod thing and he had used it in a few sessions with good results. It was flexible so it gave a nice little sting.

So we had just started playing, and I was on my hands and knees in front of him, and he was using the bendy rod thing to hit me, when it got a kink in it and bent down the middle, limp. My master frowned at it, grabbed some duct tape, and fixed the weak spot. All better! But a few thwaks later, the spot just above the tape weakend and the rod bent over again. He taped it again, and one thwak later, droop! I started giggling, and he looked at me sternly and I stopped. But then his eye twinkled and I giggled again, and he started laughing. He said "Aw, give me a hug!" and stretched out his arms. I leaped to my feet and into his arms, and he swung me around while we laughed.