Threaten to eat them! Say if they keep doing this, getting so round, at some point the human might just lose control and snack on them, since they look so juicy and delicious...
What are the best ways for a giant to scold a fat, bloated tiny for stealing food…. And what are some good insults to make sure they know how greedy and awful they are?
And then maybe the tiny panics and starts trying to scrabble away, only to realize that they’re moored down by their massive belly and can’t move anywhere. Perhaps the human even squeezes their bulging tum with two fingers to emphasize their point as they talk about how ripe and firm they’d be to bite into, packed full of delicious filling like an oversized truffle, and this makes the tiny even more scared.