Polly Pocket

'Polly Pocket' is an ongoing animated series based on the Polly Pocket toy line by Mattel, airing in 2018. The show's titular protagonist inherits a locket form her grandmother and discovers that it's magical, allowing her and her friends to shrink down to an incredibly small size.

S1E14: Swimsational
Polly balances attending a family dinner and a shrunken down pool party, the latter including her modelling for her fashionable friend Lila's swimwear. She wears a swimsuit that has a flotation device installed, and is subjected to its inflation by Lila in showing it off, though Polly then has to rush back to the dinner while hiding the puffed-up suit, as a deflator hasn't been included. Now back at the dinner table, the air is let out.