In the past few years, we have covered plenty of flexible smartphone holders here. This Giraffe Neck Pillow Phone Holder is also worth a look. You can wear it around your neck to use your smartphone comfortably in bed hands-free. You can also wrap it around your steering wheel or use it on the ground.
This pillow weighs 50g. It measures 70cm long when unfolded. You can find out more about it here.