OK I don't tell dirty jokes but her twit has obliged me to tell a joke. I will sensor the bad parts as best as I can.
A Pakistani young boy progressed in the school after paying bribes to the teachers. He reached the High school, there he came across a honest teacher. When the teacher realised this boy cannot read or write, he got suspicious. He decided to test the boy with the syllabus of earlier year, but the boy failed the test. The teacher invited the father of the boy to the school.
In the presence of his father, the teacher took different tests for lower years'syllabus, they boy failed all.
When the teacher reached the syllabus of 3rd grade. The father of the boy all of a sudden got up and ran to his home in a hurry.
He started to call for his wife as soon as he entered the house. His wife came running, the man ordered her to undress, the wife thought he is feeling frisky. .
I leave the rest to your imagination.
Let's say, the father was worried from the sudden fall of the boy.