flack out

flack out

 and flake out
Sl. to collapse with exhaustion; to lie down because of exhaustion. All the hikers flacked out when they reached the campsite. After a few hours, the hikers all flaked out.
See also: flack, out

flack (out)

in. to collapse in exhaustion; to go to sleep. Betsy flacked out at nine every night.
See also: flack, out