From Longman Dictionary of Contemporary Englishplunk (yourself) downplunk (yourself) down informalto sit down suddenly or heavily and then relax SYN plonk British English Why don’t you plunk yourself down with a good book? → plunk
Examples from the Corpus
plunk (yourself) down• I plunk down a dollar and confront my deepest fears.• Americans love to plunk themselves down in front of the TV.• Marketers usually plunk down the equivalent of $ 40,000 or so in cash, goods or services for placement.• The beverage giant wants you to plunk down your money and decide for yourself. 