The phrase you say when your are falling asleep on the couch and someone tells you not to fall asleep. You should explain why you are "resting your eyes" so it is more believable.
Wife - "Hey, don't fall asleep it is early, we need to get stuff done."
Husband - "Oh I'm not, I'm just resting my eyes, I sat infront of the computer all day at work."
(5 MIN LATER)
Husband - zzzzzzzZZZZZZZZ