My mother has a habit of sticking her hands in her briefs. I've tried onsies, she will mess with the brief area over the onsie so much she moves it out of place and makes a mess still. It does prevent her from getting it on her hands and underneath her nails but doesn't prevent the messes completely. I've used big safety pins to pin her pants to her top, she removes them or still gets her hands in even with them on.
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