I don't have anything for or against it, but I really hadn't heard of it as a distinct sexual activity until recently.
Some folks seems to like it a lot, AND HARD some more gentle.
But I'm not sure I see where it fits in - part of foreplay or part of the actually screwing? Best when doggy style? Maybe like reins in RCG. LOL
Maybe its something I'll offer my partner someday, but try to explain it first.