In bed, under the bed covers.
(idiomatic) In secret.
Source: en.wiktionary.orgHomework is not an option. My bed is sending out serious nap rays. I can't help myself. The fluffy pillows and warm comforter are more powerful than I am. I have no choice but to snuggle under the covers. Laurie Halse Anderson
And I guess that's why they call it the blues. Time on my hands could be time spent with you, Laughing like children, living like lovers, Rolling like thunder under the covers. And I guess that's why they call it the blues. Elton John
Naps are the key to relieving stress. When you are working on two hours of sleep, the fact that cheese comes on something when you ordered it with no cheese is enough to send you crying under the covers for an hour. Keri Russell
I've loved 'Vanity Fair' since I was 16 years old. You know, we're all colonial hangovers in India, steeped in English literature. It is one of these novels that I read under the covers at my convent boarding school in Simla. Mira Nair