Sometimes a more discreet euphemism for "being on your period" is preferable, such as...

Miss Scarlett's Come Home to Tara

Trolling for Vampires

A Dishonorable Discharge from the Uterine Navy

Saddling Old Rusty

Feelin' Menstru-riffic!

Clean-Up in Aisle One

Massacre at the Y

T-Minus 9 Months and Holding

Game Day for the Crimson Tide

Panty Shields Up, Captain!

Taking Carrie to the Prom

Playing Banjo in Sgt. Zygote's Ragtime Band

Ordering l'Omelette Rouge

Arts and Crafts Week at Panty Camp

Rebooting the Ovarian Operating System

Aunt Floe is visiting