2
general::
plump sth up
[ M ]
to make something fuller or fatter
• She went round plumping up the cushions.
• Lips can be plumped up with injections., plump (sb/sth) down
[ M ] informal
to sit down suddenly and heavily, or to put an object or child down suddenly and without taking care
• She plumped down next to me on the sofa.
• [ R ]: He rushed in and plumped himself down in a chair.
• Joan sat down at the front of the bus, and plumped her bags down beside her.
Cambridge-Phrasal Verbs