you should be sleeping 

Usually a phrase used when talking over social media or text; when someone is messaging you and they don't want to talk.
They use the time of day as an excuse to ignore you.

You: 'hi how was your day'
Them: ' you should be sleeping'

You: 'oh I'm not tired'
*message seen 10.32pm*
(Next day)
You: "how come you didn't reply to my message?"
Them: "I thought you were sleeping"

you should be sleeping by Definamy November 20, 2014