Are you talking about spanking, or insertion? I know that when I spank my partner, I typically set up a rhythm. Then, of course, every now and then, I pull on of the blows so as to not make contact. Lets her know that anticipation and tensing just doesn't work. AS far as insertion goes, well, my various lovers are to fond of different things to deal with any sort of regular rhythm.

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On the kinkometer, my kink measures as a sine wave.