I'm not pretending I know Sadista's mind.
But from what I DO know: you don't ask Sadista when she'll arrive. You will see her return when she is damn good and ready, and it will be harkened by the sharp sensation of a stiletto heel poking deeply into the flesh of your back.
lol.
Otherwise they'd call her "Submissiva".
But like many others I wait for her return patiently, quietly, and with a compulsion to hide the fireplace poker.
Deet