expression, ichidan verb
sit down firmly; settle down; plant oneself
Implies sitting down with determination, often for a long stay or to take a firm stance. More emphatic than 座る.
彼は応接室のソファに尻を据えて、なかなか帰ろうとしなかった。
He planted himself on the sofa in the reception room and showed no sign of leaving.
I'm ready to sit down firmly at the negotiating table.