Hit the sack.
[Slang] HIT THE SACK. - Discover Quirky Expressions for Saying You're Going to Sleep
Go to bed.
Hit the sack" doesn’t mean you literally hit a sack, but it’s a playful way to say you’re going to sleep. This saying comes from the old times when mattresses used to be filled with sacks of hay.
Example Sentences
I'm exhausted, so I'm going to hit the sack now.
I'm very tired, so I'm going to sleep now.
He usually hits the sack early after a long shift.
He usually goes to bed early after a long day.
Before exams, she hits the sack at 10 PM to get a full night's rest.
Before exams, she goes to sleep at 10 PM to get a full night’s rest.