Chucking (sometimes called chunking or just palm muting) is a strumming hand technique that mutes the strings before strumming them to give a percussive sound. It's used in a lot of ukulele songs and I'd recommend you get to grips with it just as soon as you've mastered a few basic strumming patterns.
How do you chunk on a ukulele?
The chunking technique is used to add a percussive sound to your strum; basically the equivalent of clapping, using your strings. To chunk, strum down using three or four fingers of your right hand, then immediately dampen the strings with the side of your thumb (while your thumb is pointed towards the ground).
What is Chuck guitar?
“Chucking” is a common technique with acoustic guitar, where open strums and dead note “chucks” are alternated to create a rhythmic pattern, and it is a primary technique used for playing chords and single notes in creating funk guitar rhythm parts.