To prevent overheating, why not turn laptop upside down?

Solution 1:

If you have the space, open the laptop 60 degrees, then turn it so the side. Put it on something soft to prevent scratches. I've used this setup in the past with my old Macbook which could heat up to 90 degrees celsius.

See this ice pack tip as well!

Solution 2:

The dust problem may be the only concern for doing this, but as you stated is avoidable. I regularly do this with my laptops if they are running and I'm not using them.

The only thing you don't want to do is rotate the laptop while it is running IF it has a mechanical hard drive. The momentum of the spinning disks could cause the heads to hit the disk if you're moving it too quickly. I imagine this isn't a concern for you since you said it's basically used as a desktop.