Antonyms for the word "plunks down" include various verbs that describe a graceful or deliberate movement of sitting: perch, settle, alight, land, take a seat, or ease oneself into a chair or other seating. The term "plunking down" generally connotes a less sophisticated, less formal action - perhaps dropping into a chair with a thud or plopping onto a sofa with little grace or elegance. As such, its antonyms tend to convey a sense of elegance, poise, or careful consideration. Choosing the right verb to describe one's actions can help convey the intended meaning of a particular action or emotion in a precise way.