plump up
Upper Intermediate (B2) neutral
To make a soft thing like a pillow or cushion bigger and puffier by hitting or shaking it
"She plumped up the pillows before the guests arrived to make the bedroom look inviting."
Hear it in context
Martha Stewart Unfiltered: The Homemaker, the Mogul, the Myth
Molly Sims · 40:45
but you are going to plump up your skin.
Gladiators, real housewives and the pull of reality TV | Throughline
NPR Podcasts · 39:48
bottles to plump up their lips like Kylie Jenner.