It's a little harder for a guy, since he can't just mutter, "Female problems" when someone finds a bag and hose.
Several of the men I've known online over the years had fairly good hiding places for their equipment, and kept it to a minimum. Often it was among tools, in a garage, basement, or workroom, among hobby supplies, pool chemicals, anywhere the household members were not likely to snoop.
At least one kept it in a metal toolbox, old and rusty, which he kept locked with a stacked-steel padlock. He worried about the worst-case scenario in which he died and his wife and family had to go through his things. Finding a locked box, beat to hell and rusting, and no key, he hoped they'd discard it. I remember he picked up the box for next to nothing at a garage or estate sale and knew exactly what he'd do with it.
I'd recommend visiting a discount or drug store, maybe not your neighborhood one where they know you or you could see a neighbor, and buying a douche bag like this one: http://www.drugstore.com/qxp72138_333181_sespider/goodhealth/faultless_premium_combination_douche_enema_and_water_bottle_system_2_qt_capacity.htm Naturally, you'll also want to pick up some toothpaste, a magazine, some light bulbs, Scotch tape, and enough other miscellany to deflect undue attention from your main purchase, right?
The same system is sold at many online stores, too, including Amazon. If you make a purchase from an innocent online retailer in the next month or two, you can always act like it's a Christmas gift and refuse to let anybody see what's in the box. (Aren't you smart!)
Merlot, semi-devious