I'd run outside, heart in my throat...and wake him up.
Yep, he was just napping and sunning himself. You'd think I'd learn, but it would about give me a heart attack every time.
When I found him like this this weekend though, I suspected the worst. It was too cold, not enough sun. Come on, Stewie, get up, shake yourself, and look at me like I just disturbed your nap. Please!