A term used primarily in Kendal, Cumbria, UK to describe the monthly torture women must endure. As per the phrase "It's like having your spine slowly ripped out from the bottom whilst simoultaniously birthing a large watermelon".
Arg, can't come out tonight, the watermelons are attacking
Oh, woe, for I am suffering with watermelons
It's watermelon week, bring me weed and chocolate