HA! mine isnt sewn so fancy but I have three camo fleece blankets for that purpose. two are in the closet, thanks to the wife but I do have one on the couch that I use regularly. got the material at a fabric store, roughly 2.5 meters by about 1.75 meters wide. got my momma to sew a hem of sorts rounf the edges, its great! totally warm and since its camo you can barely seem e if I hunker down and close my eyes!
My personal inclination when temps drop below the teens is to simply stay indoors in a pleasantly warm place- I got a big plenty of below zero work logging in Montana and playing cowboy as a youth- but I know a few madmen who will hunt deer from tree stands in -20F temps. Their method involves layering clothing and sitting in a sleeping bag while on stand. -Nigging fruts.
I love that idea, in fact, I asked for a pink blanket for Christmas. ( Palmer shredded my old one, playing as a puppy) Nothing that cool, but I think it is going to be my favorite gift! After being in the sun all day, John likes it freezing in the house at night.
He did, why? John recently lost 20 lbs or so and he hasn't needed his blood pressure meds since. The doc always told him, loose some of that weight and you will be fine. He monitors it frequently though.
No, that's just it - it ain't a sleeping bag. The simplicity and function from just folding the bottom up a foot and sewing the sides is the coolest part. Definitely NOT a sleeping bag... not as complicated or expensive. I'd like one!