I have a laptop that gets pretty hot. I use a plastic tray table with a padded bottom on it while I'm using the laptop in bed or on the sofa, but the laptop gets hot enough to melt the plastic (it used to have grippy dots on it but they've melted away from the laptop heat).
Do you use a tray/table for your laptop? Which one and what do you like/dislike about it.
Have you considered sitting on chair with a desk in front you? If your talking egronomics then thats a pretty good start.
Sounds like you need more air between the laptop and the surface.
I've found it useful to get self-adhesive slightly-rubbery plastic hemispheres and put them on the bottom of my laptops - particularly after the "feet" they come with fall off.
You can find them in DIY shops near furniture protectors (e.g. self-adhesive bits of felt to protect wooden floors from being scratched by chairs).
Consider buying a docking station if they are available for your laptop. Those can have special fans and such for cooling.
Although I don't use it myself (never code in bed), the Tablett Laptoptray by "Magazin" might give you some idea for your problem: Use a soft/adaptable flat cushion below for comfort and a rigid plate on top to keep the laptop standing on its own feet. The two parts are connected with some velcro strips to avoid separation.
If you are into DIY you might find these instructables useful
Did you try to open it and clean all the dust? My friend did that with his 2-year old laptop and temperature has dropped by astonishing 30 C...