My left leg has fallen asleep!
John Doe, fell asleep 1 January 2001.
I... I don't think I can fall asleep.
Ben can fall asleep in the middle of a conversation.
If you don't fall asleep on me.
This place is creepy. I don't think I can sleep with bugs the size of my hand just waiting for me to fall asleep so they can crawl all over me.
He'd just started to fall asleep when he sensed the intruder.