Via Gigglesugar, this Tampax ad.
Description: Woman in red bikini jumps into swimming pool, swims a lap of breaststroke, gets out again. Bloke in pool looks astonished as water has suddenly dropped to knee height.
As one gigglesugar commenter said, “So this woman now has 500 gallons of water trapped in her vajayjay?”
While we’re on the subject of menstruation, there’s a new menstrual cup on the market, Miacup, from South Africa. It looks pink on the website, but users say it’s more of a purple colour up close. It’s more expensive than the other cups, but – purple!