So, it's like a normal duvet, see, right, yeah, but about 12 inches from the top, right, you cut two holes, yeah? And over these holes you sow a pair of long-armed gloves, see, yeah, right, and they're padded or whatever for extra warmth, yeah? And so you can lie in bed, right, see, with the duvet like right up to your neck so you're all snug and warm and that, yeah, right? But you can also hold a book and read it!
Clearly both duvet and cover will have to be synchronised.
This is my chance to make up for not pursuing the idea I had for price comparison websites back in, um, 1996 or so.