air (one's) belly
slang To vomit. When I had the flu, I spent most of the time airing my belly.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
air one's belly
Fig. Sl. to empty one's stomach; to vomit. I had a bad case of food poisoning and was airing my belly for most of the night.
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.