The screen cap is authentic. That is Misty's sister, Lily. Misty's sisters were only in a handful of episodes. I don't remember which this appeared in, if I saw it. It is a recall of something that happened, though, and is most likely a still image. What you see, is what happened.
It's pressure point manipulation, not tickling.
And that's all that happens in the scene. You just see a still shot of it.