You know all about Disney's animated princesses, dwarves, and fairies. You might even know about his wartime propaganda cartoons. But there's one animated short from 1946 that you might not have heard of. It's called "The Story of Menstruation," and no, this is not a joke.

This, obviously, is not standard Disney fare. How did this little gem come to be? According to Film Threat, "World War II shut off the lucrative European theatrical market, which cut off a significant source of Disney’s revenues. At home, the ambitious feature Fantasia was a major commercial failure, draining more money from the company treasury." In need of funds, Disney began taking commissions from the government and corporations, creating films like “The Right Spark Plug in the Right Place” for the Electric Auto-Lite Company and “The ABC of Hand Tools” for General Motors.

"The Story of Menstruation" was commissioned by the International Cello-Cotton Company (now Kimberly-Clark) and features a female narrator who matter-of-factly gives young girls the facts and some "helpful" advice, including: Don't get tired, emotionally upset, or catch colds—it will throw you off your schedule; keep a personal period calendar, a "useful record of past performance" that "comes in handy when you have to plan ahead"; make sure to bathe during your period (that myth about it being ill-advised is just not true); and feel free to exercise, as long as you don't go to extremes.

Most girls, the narrator notes, will have no trouble with their periods, but some will feel a little less peppy or experience more discomfort. "Don't let it get you down," the narrator advises. "After all, no matter how you feel, you have to live with people. You have to live with yourself, too. And once you stop feeling sorry for yourself and take those days in your stride, you'll find it's easier to keep smiling and even tempered. You can do practically everything you normally do." Also: Don't slouch. "Slumpy posture is just as bad inside as it looks outside," the narrator chastises. And avoid constipation, too. (Seriously.)

The short film was played in health classes up until the 1960s, according to Film Threat, and was accompanied by a handy booklet, "Very Personally Yours," filled with information from the film and more handy advice. You can see a full PDF here.