Place a W-series Thinpad on your bare legs on a warm summer day (think you can just still survive/think at all without A/C). You will want to get it away as you can't sweat well under it, and it's dumping some heat into your blood. That's it, despite some discomfort you won't mind it. And apparently the make them with more TDP than apple seems to be able to handle, but instead of an i9 they appear to jump directly to a Xeon. Those start at over $3500 in base configuration though....