I have a Targus cooling pad that works pretty well for that. It's like a thin plastic tray thing with vents and a USB-powered fan to provide extra cooling, but I mostly use it without the fan to elevate my laptop off my lap and allow for extra airflow. Something similar might work well for your use case.
That said, I've noticed my laptop's fan will start to make an obnoxious rattling noise if I use it on my lap for too long. Fan rattle is a known issue with my laptop and it goes away once it's sat on my desk for a while, but it can be annoying so YMMV.
TIL! Thanks for the clarification.