flack outand 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.
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.
in. to collapse in exhaustion; to go to sleep. Betsy flacked out at nine every night.
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.