MICHEL: Stop jumping like a Mexican bean.
Mexican jumping beans are not really beans, but seed pods of the plant Sebastiana pavonia, native to Mexico and Costa Rica. The seeds can become inhabited by the larva of a small moth, and if it becomes warm, it will move to eat, causing the seed to “jump”. Holding one in your hand will warm it to the point it becomes quite lively. They are sold as children’s novelty items in the US, and it is common to say that an excitable child is hopping about “like a Mexican jumping bean” .
The Annotated Gilmore Girls 