My chiropractor has instructed me to stop looking down at my laptop while I'm sitting on the couch. It is bad posture. She insists that I get a table and chair in the living room. Spouse does not approve.
I have looked at a few of the other instructables including the "tables". They look like a lot of work to build. OK, maybe only a few hours... I'm lazy. Also, my wife does not want a big bulky wooden thing to sit around in the living room.
Solution: Twine/Rope/String. 2x Safety pins. One big sofa cushion. 2 knees.
Step 1: Attach rope to cushion with safety pins.
Step 2: Insert laptop
If the hinges of your laptop are on the outside of the screen and right near the edge preventing you from stringing it up you could try using velcro on the cushion and on the bottom of your laptop.
Step 3: Lie down and work.
Easy to put on and off your knees if you need to get up to the bathroom and keep the heat off your legs too. Might not be so great for ventilation on your computer, but that is not a problem for my mac air.
I actually leave the rope and safety pins on the cushion and wife approves. Simple solution.