
NEMO
Disco 15 Series
Spacious spoon shape, but bulky and inconsistent warmth.

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I have a Nemo Jam, which is shaped like the Disco. I'm a side sleeper and I absolutely love it. I don't think I could sleep in a mummy bag.
The Nemo spoon shaped bags, TR Boost or BA Torchlight are all nice and accommodating for flamingo type sleepers (I am one as well.) Also consider a quilt!
i’m 5,3” and i have a women’s nemo bag that fits just right
I sleep like you and it’s been the bane of my backpacking experience for the last 40 or so years. A few years ago, my husband bought me a Nemo side sleeper sleeping bag for Christmas. I was a little skeptical, but it actually helps a lot. I can’t remember what it’s rated to. It’s definitely not for extremely cold nights, but I don’t know if there are options in that. For car camping one of the main things I do is carry a wider pad. That way when I pull my knee up into the side, it at least stays on the pad and isn’t on the cold hard ground. As someone else mentioned, I also keep some extra gear in a stuff sack, and use that underneath my knee, which helps for warmth and back comfort.
Just got back from Algonquin where the temps dropped to 3 degrees C. I was comfy in my fairly new -9 degree C Nemo down bag wearing long base layers only, but I felt if it got below freezing I would need some additional layers. Other commenters are giving good advice when they say a good sleeping pad makes a big difference, especially if the ground is already cold (not just air temps dropping at night). Don't trust temp ratings of cheap bags and aim for something with a rating 15 degrees below the coldest you could expect it to possibly get.
Nemo down 15F is my favorite. I felt warm sleeping when outside was below 30F. Wait for the next sale in REI you can snag it for nice discount.
I love my down 15* Nemo bag. It's a huge warmth difference compared to my synthetic 25* Nemo.

NEMO
Disco 15 Series
Spacious spoon shape, but bulky and inconsistent warmth.
Hammock Gear
Classic Burrow 20°F
Budget-friendly quilt; very warm, but not ultralight.

NEMO
Disco 30
Roomy spoon shape, but bulky and prone to zipper snags.

Katabatic Gear
Alsek 22°F Quilt
Premium quality, very warm, but high price for weight.

Neve Gear
Waratah
Great warmth-to-weight and value, but untreated down.

Ranked #1
NEMO - Disco 15 Series

Ranked #1
Kelty - Tru.Comfort Doublewide 20
Ranked #1
Enlightened Equipment - Revelation APEX

Ranked #1
NEMO - Disco 15 Series
Ranked #1
Hammock Gear - Classic Burrow 20°F

Ranked #1
NEMO - Disco 15 Series