1
general::
Phrase(s): plunk (oneself) down
to sit or fall down hard. • Nancy pulled up a chair and plunked herself down. • She pulled the chair up and plunked down. • She plunked herself down in the middle of the kids and began to sing., Phrase(s): plunk someone or something down
to place, drop, or plop someone or something down hard. • He picked her up and plunked her down in a chair and began to shout at her. • Sally plunked down the book in anger.
McGrawhill's American Idioms And Phrasal Verbs
2
general::
Throw or place or drop heavily, as in He plunked down the money and walked out, or It was hot work, so after an hour we plunked ourselves down in the shade. [Late 1800s]
American Heritage Idioms