Hit the sack

Meaning:

If we hit the sack, we go to bed to sleep. This expression is quite common in everyday, spoken English, but rarely used in formal situations. We usually use this one if somebody goes off to a bedroom to sleep.

Example sentences:

1. I’m going to hit the sack now.
2. What time did you hit the sack last night?
3. It's time to hit the sack!

Example dialogue:

Two brothers are talking about going to bed.

A: I'm getting tired. I think I'm going to hit the sack.
B: Oh, come on. Stay up and watch the rest of the movie.
A: OK. But I'm hitting the sack as soon as it ends.
B: Sounds good. I will too.

Practice:

What time do you usually hit the sack?