I didn't think this belonged in the Ideas forum, 'cause it's something that can only be fleshed out with contributed possibilities, so...
The premise is the story that focuses on Kasumi supposedly getting angry. It ends when Ranma is blamed (he didn't do it) for Kasumi's favorite cup being broken, and as "punishment" Kasumi pokes him on the forehead. What if she had hit (intentionally or not) a pressure point? What might be the effect be? Is it truly a punishment, bad, or something else? Would it effect Ranma mentally, physically, or both?
I've thought of too many things, and that's why I didn't think it would be a good idea to pick one for the Ideas forum, since I was likely going to get a bunch of alternative effects and reasons in response. I figured I might as well give it a platform.