I use a cellulose one from SleepCountryUSA that you can breath through, but is totally waterproof, on ALL our beds. No sweating, crinkling, or ripping.
If you have a storefront near you the have mason jars filled with blue water, and sealed with a square of this stuff & a rubberband
You can tip it upside down and make bubbles (blowing into it) but even sucking of shaking won't let the liquid through. The holes in the backing are too small for water molecules, but big enough for air molecules.
The other size is super short terry cloth (teeny teeny tiny, smaller than baby towel terry), that help soak up liquid so it doesn't just run off the side.
NOT cheap. About $100 for a twin.
I'd pay $100 a year (going on year 6 on the oldest ones), which still work perfect. GREAT stuff.
I got some for our new mattresses a few years ago, and the still look brand spanking new. With boys. Dogs. Stomach flus. Visiting "potty trained so no pull-up needed" toddlers, sexcapades, breakfast in bed, etc.
AWESOME.
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They're fitted sheet type. The go directly on the bed, then sheet over.
NIGHT TRAINING HINT:
- "Make" the bed 2-3 times, with incontinence hospital pads / puppy accident pads under the sheets. As they accident, just strip off the first layer of bedding, and you've got clean dry bedding underneath. Lib the wet ones in the wash. Easy.
- Try NOT restricting liquids. Bladders just send weak messages to the brain drip and leak when mostly empty. When they're full full full ... They send Urgent! Messages to the brain. When training, URGENT! messages are needed to break through the sleep cycle. If you push liquids, instead of restricting, its usually only a couple nights of accidents, instead of months.