It was once that Pepito was in class

It was once that Pepito was in class and his teacher told him I want them to bring a little bottle of pee tomorrow.

They all go home and when they get home, Pepito says to his mother,

Mom, I have to take a jar of pee to school tomorrow.

His mother gives him her bottle and his sister who was pregnant plans to do something bad to him

and changes the bottles,

Pepito arrives at school the next day, says teacher Rosita, you are very well,

Lucía, your kidneys are a little bad, drink more water.

Pepito “Pepito” you are pregnant and Pepito says to his friend: once, once, you told me that nothing was going to happen to me