I generally read manga or novels.
Since you actually get sleepy while reading characters and stuff, I recommend it.
Hiromoto Ruli
Listen to music I like, watch YouTube.
Yonemura Kirara
Listen to the radio.
Kubota Nanami
Read shoujo manga!
Nakayama Natsume
Watching YouTube.
Watching movies or dramas makes me purposely not sleep.
Nishizaki Miku
Watch videos, use the time for my hobbies!
Kitahara Momo
It's "Endlessly watch binge eating videos, or Think endlessly about what kind of worlds there might be beyond outer space".
Tsutsui Roko
Close my eyes and think about various things in my head!
If it's stuff like what I'll be doing tomorrow, or singing songs, I fall asleep before I know it!