Cropped In Her Cage
You might enjoy this nifty scenario I found over at Sex And Submission, featuring a riding crop, an iron cage, and the lovely Sandra Romain:
Spanking Blog: Adult Erotic Spanking At Its Best
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Brutal Pussy Spanking Movie:
Detention House 2: Collective Punishment Extreme
"...the girls are strapped to the bare military metal beds in an extreme position, with their feet by their heads, spread wide, so their butts, pussies and anuses are fully accessible..."
Hmm… could be difficult to land with those bars in the way. I’d say a vertical downward stroke is the best bet!