I take a lot of naps now, almost every day, usually in the early afternoon between 1 and 4 pm. I have a really comfy couch with is similar to a futon but doesn't fold out but has a futon cushion. It's just long enough to stretch out with a pillow for my head and feet against the pillow at the other end.
And I'm usually asleep quickly. The length of the nap depends on how tired I am that day but last from short, usually 15-20 minutes, to long, usually 30-45 minutes. And I always wake up with a sudden start where I hear myself breath and my mind is awake.
Every now and then I lie there thinking how lucky I am to have that moment when I feel myself breath in and my mind awake up because if I didn't, I wouldn't know I had died. I think death must be similar if it occurs while you're sleeping, you just don't wake up.
You don't feel yourself breath and you don't feel your mind wake up. You never know it, you never realize it and you never see the world again. The last nap.