As a side sleeper I've always had a hard time getting a good nights sleep when I'm out camping. Without a good pillow my neck doesn't get enough support and I have often woken up with a sore neck or cold hands when I've held them under my head in cold weather. I have tried using both inflatable pillows and some of the "normal" pillows offered by several of the outdoor gear manufacturers. The inflatable ones have been okay in cold weather when I've had my head wrapped in a sleeping bag but they just won't stay put and often slides away after a short while. The "normal" pillows are often not thick enough to give my neck enough support. They do also add extra weight and take up extra space in my bag. For a good nights sleep it's definitely worth it but if it can be avoided, why not?
I've also tried using the climbing ropes with good result but if they are wet or icy it's not very nice to bring them inside the tent. A stuff sack filled with leftover clothing/stuff works pretty good and doesn't add any weight but it suffers the same problem as the inflatable ones, it usually slides away during the night. With a fleece wrapped around it to help wick moisture away from my skin it's also pretty good in warm weather when I have my head right against it.
When I was packing for a multi day backcountry ski and climbing trip last winter I got an idea, inspired of how some people put a piece of cord on their quilts under their sleeping pads to keep it in place I attached a piece of fabric to the stuff sack of my Exped Downmat that would go around the sleeping pad and keep it in place during the night. I didn't want to use cord since I would need much higher tension on it than with a quilt and I was afraid of wear on my sleeping pad.
I made a quick prototype which worked great during that trip but since I'm usually bringing my Neoair even during the winter and the stuff sack for that one isn't big enough to use as a pillow I've just made a new one to replace the Sea-to-summit Dry Sack I have used for my Custom Robert's sleeping bag.
It stays in place really good thanks to the straight sides of my older NeoAir. The newer ones are tapered at the ends to make them lighter and I suspect that this solutions might not work as well with those.
The material I used is pretty cool, it's rip-stop nylon with a silicone coating on one side and a PU-coating on the other side. That means you get the strength(kind of) of silnylon but you can tape the seams on the PU side to get a fully waterproof bag. Sea-to-summit uses the same kind of fabric in their Ultrasil Dry Sacks. IIRC the weight is 65 g/m² for this fabric.
Webbing on one of the sides and two layers of thin piece of PET plastic glued together in the other. I have done quite a bit of testing of different materials lately to see what can be used to stiffen up the edges in roll top closures and I think PET plastic is a really good choice, it doesn't seem to fatigue and break as quickly as some of the other plastics I tried when subjected to a lot of bending back and forth. You can get a strip from a coke bottle and flatten it by ironing it really quickly on medium setting.
I also made a fleece cover for warm weather use. I prefer cotton for the nice feeling of it but fleece wicks moisture faster and with only a thin layer I think that's the right choice. The fleece I used is quite heavy at 280 g/m² but with a very high loft so should be good for wicking moisture away so I won't wake up with that clammy feeling.
To make sure it stays put during the night I made it so it wraps around the dry sack a little bit, I hope that'll be enough, otherwise I'll have to add some kind of strap or worst case a piece of velcro.
The band that goes around the sleeping pad is also offset a couple of centimeters from the edges so the fleece will wrap around the sack better.
The dry sack holds about 8 liters and weight 46 g and the fleece cover's weight is 53 grams.
Hope it's of help to somebody! :)
