Been gaming for years with macbooks on my lap and it is fine if you have a speck case as it absorbs a fair bit of the heat.
Saying you can't use laptops on your lap is a load of rubbish, the only thing likely to cause problems is if you wear that much baggy clothes that you block all the air escaping from the laptop, the chance of that happening is pretty slim.
You do need to make sure it gets proper ventilation. What sometimes happens is people put it on the lap, on a blanket or pillow or something and that pretty much plugs up the backside vents. THAT is not going since the hot air has no easy place to go. So, make sure there is SOME space underneath and you are fine.
Also, the foot plugs are pretty good sized, so the metal won't scratch the surface of your desk.