one's head off

Adverb

 * 1) Without restraint, hesitation, or inhibition; endlessly.
 * 2) * 1998,, , New York: HarperFlamingo, p.103,
 * Late in the fall, the milky green bushes surrounding every house and path suddenly revealed themselves as poinsettias. They bloomed their heads off and Christmas rang out in the sticky heat
 * 1) * 1998,, , New York: HarperFlamingo, p.103,
 * Late in the fall, the milky green bushes surrounding every house and path suddenly revealed themselves as poinsettias. They bloomed their heads off and Christmas rang out in the sticky heat

Usage notes
This expression is most often used with verbs expressing speech or other forms of vocalization, such as howl, laugh, sneeze, snore, squawk, talk, yawn, yell. An adjective may be used before the word head, for example: They were giggling their silly heads off. Other verbs that commonly occur with this expression are eat (also drink, smoke), lie (i.e. tell falsehoods) and work.