Now that the nights are drawing in and (with the exception of today) the temperature has started to drop, it is perfectly acceptable - nay, expected - that you should spend 23.5 hours a day under the duvet. If your Ooman is willing to move your water, food and litter tray for you, by all means spend that remaining half hour under there too.
If your Ooman tries to shoo you out from under the duvet, be sure to do the same to your Ooman. I recommend chasing any toes that may peep out of the bottom of the duvet, and biting Ooman's nose (gently, but with meaning) 10 minutes before the alarm goes off in the morning.
If you've noticed your Ooman is a bit snotty, restrict yourself to the toes until it passes.