The stepmother accidentally ended up on her stepson's penis... or was it not accidental?

Yeah, it would take some effort to mix up bedrooms in a house where you've been living for almost two months. And to mix up your stepson's penis with your husband's... well, that's hardly a coincidence. Coincidences are not accidental, as one kung fu master said, so you can safely bet your house that the sexy stepmother deliberately came into her stepson's bedroom and sat on his boner because her husband couldn't satisfy her.