The Eridians watch each other sleep and so sleeping and watching often co-occur in Project Hail Mary.

A form of “sleep” occurs in 93 paragraphs and a form of “watch” occurs in 96 paragraphs.

The two occur in the same paragraph 18 times. In one case, they are unrelated (11.124).

But there are 17 times where they are associated:

12.119 He wants to watch me sleep?
12.131 He wants to watch me sleep.
12.145 Every night, I sleep in the tunnel. He watches. ... But he really doesn’t want me to sleep without him watching.
12.219 He watched me sleep, so it’s only fair he offer to let me watch him.
12.231 Eridians watch one another sleep. It’s a thing.
12.250 We stay like that for a moment. “I’ll watch you sleep.” 13.122 ...once every eighty-six hours or so, Rocky sleeps in the tunnel and wants me to watch.
16.174 “You watch me sleep, question?”
16.204 “I…sleep…” he slurred. “You…watch…question?”
16.206 “Yes, I watch. Sleep.”
17.009 “You don’t have to watch me sleep. It’s okay.”
22.165 “Sarcasm. You sleep. I watch.”
25.019 The whole “watching me sleep” thing doesn’t creep me out anymore. If anything, it’s comforting.
25.127 “You sleep. I watch.”
25.133 “You sleep. I watch...”
28.039 It feels wrong to sleep without someone watching.
30.052 “Adrian is going to sleep soon, so I have to be there to watch.”