Are there any abdominal exercises I can do while lying down before bed?

I feel like my belly fat is gradually increasing since I stopped exercising.

I'm getting less and less inclined to exercise, and I just keep getting more and more lazy.

I'm sure some of you can relate, but whenever I lie down to sleep, I always think I should do at least one exercise.

Are there any abdominal exercises I can do while lying in bed?
My abs and sides are great!