Whereas a normal woman's vagina can only take so much punishment before becoming sore, a woman with a "double-jointed" vagina can have sex with multiple partners (4+) throughout the day with no ill effects.
the crawl (often seen in horror movies) when someone (usually a dead person) crawls freakishly usually putting their feet in front of their head in the process (thus double-jointed). If you have seen the grudge, the grudge boy does the double-jointed-monkey-crawl down the stairs.
What a double jointed pussy is; when a woman’s vagina can expand to two times the size. A double jointed pussy can fit up to 4 penises. A woman can have intercourse with a double jointed pussy for up to 20 times a day.