Lower Back Caning?
It’s possible we just have a bad camera angle, but it looks for all the world like this poor young lady is getting a painful caning on her lower back:
From Lupus.
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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..."
A rope, belt, or whip to the back is a classic painful punishment. Anything hard sounds dangerous on the back.