From Longman Dictionary of Contemporary Englishplonk yourself (down)plonk yourself (down) informalSITto sit down heavily and then relax We plonked ourselves down in front of the telly and opened a couple of beers. → plonk
Examples from the Corpus
plonk yourself (down)• He was built like a brick shithouse and he plonked himself down right in front of the stage. 