SMA+Mexican+bean

//noun//**
 * Jumping Bean
 * the seed of any of certain Mexican plants of the genera Sebastiania and Sapium, of the spurge family: the movements of a moth larva inside the seed cause it to move about or jump. ||

Also called Mexican jumping bean. 1885–90, //Americanism//
 * Origin:**

[]

The poem is saying that the person has lots of energy, just like a Mexican Jumping Bean.