plonk1 [transitive always + adverb/preposition] especially British English informal
1 also plonk something down
to put something down somewhere, especially in a noisy and careless way [= plunk American English]
You can plonk those bags down anywhere in my room.
plonk something on/onto/beside etc something/somebody
He plonked a couple of glasses on the table.
to sit down heavily and then relax:
We plonked ourselves down in front of the telly and opened a couple of beers.