Here you can see Dave on what might be his favorite napping location of all. The opportunity to use this napping location only presents itself occasionally, but Dave is always ready to capitalize for a great nap. A lesser cat might not even notice the opportunity until too late.
What you see here is a napping location that already has a similar temperature to Dave's body, and is also extremely comfortable. There is one other drawback though - the object is not stationary. This may be what caused Dave's concerned facial expression in this photo.