Beyond using the sleep cycles to determine nap and bed time, they also show up on their own every night in our son’s waking pattern. He, at 6 months, woke every 45minutes throughout the night. There was a medical reason for the waking, which you can read about in Our Story , but the timing was still controlled by his biological clock. If you look at the diagram above, the transition from REM to the next stage is exactly where we see wakings. At 17 months, he naps either for 90 minutes, 135 minutes or 180 minutes. During the night, when he wakes, I look at the clock and only when he is sick or teething is the waking NOT divisible by 90 minutes.
The best way I can describe the feeling of napping is that you lie down or sit somewhere, and first focus on relaxing. Relax your muscle groups one by one, from your neck all the way down to your toes. Take a good minute or two to do this properly. Then finally you relax your thoughts. Let them drift off. It's important to gently nudge those thoughts towards more relaxing topics – you won't nap very well if you're rehearsing a conversation with the boss – but at the same time, they need to largely drift on their own. Keep your eyes closed, your body relaxed, and let your thoughts meander from subject to subject without much order.