Kefir is a fermented milk drink that originated with shepherds of the North Caucasus region, who discovered that fresh milk carried in leather pouches would occasionally ferment into an effervescent beverage. It is prepared by inoculating cow, goat, or sheep's milk with kefir grains.
Often tagged with images on pixiv as a cheeky euphemism for cum.
A well-known meme, "No, it's kefir" originated in TV commercials for "Sennen Kefir" of Yazuya Co., Ltd.
