Rough-housing. My little brother was trying to catch me in a very tight spot, and I was on all fours, so it was basically me leapfrogging out of the way. Generally I don't have a problem with it, since I'm freakishly (at least that's what mum calls me, then again, me too) flexible, but, this time I land on my foot and my momentum used the top of my foot as a ski. Ouch.
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