Well, I remember playing 'SPUD,' including the spanking-oriented loser's forfeit, with my female cousin and sister, usually plus one or two other children, back in the early-to-mid-1960s.
There were sometimes no numbers involved in this less formal version, though, whoever was "it" simply yelled another player's name as he/she threw the ball into the air. However, the 'spanking machine' payoff for the loser was practiced the same basic way.
While I'm opposed to children deliberately being influenced by adults to sexualize the spanking experience (although this Library is proof that it can happen unintentionally), trying to "shelter" young kids from the fact that it exists makes little sense to me.
Indeed, it strikes me that attempting to prevent a child from being exposed to anything about spanking might give it a certain "allure of the unknown"...

--C.K.