I agree with the majority of the comments, in my professional cuddling role I don't fall asleep unless it's an overnight session. If a client wants to nap, great! But I am awake and fully present.
If it's an enthusiast or friend situation, then naps are awesome.
But I think the best plan is communication and consent always. I have had clients who struggle with sleep so if they can relax enough to nap, that is a great thing! I always just ask if people want to be woken up or if they are comfy with being asleep for part of the session.