In the event of a tsunami, Wolverine, your forehead, and a stool will all be immersed in it. You will become immersed in the tsunami after it hits because tsunamis are gigantic and bring a lot of water. Now you and your forehead are immersed in the tsunami along with Wolverine and a stool.
Still immersed, the stool floats over and hits you in the shin (しん). The tsunami gave the stool a good push and while it was fully immersed, it ran into your shin. It really hurts.