A Hard Lesson...

Antonio came home from school one day and his granmother asked him what he learned. He said the teacher told them all about penises, vaginas and masturbation. The grandmother slapped him hard across the face and told him to go to his room. Antonio rushed upstairs crying.
After a few minutes the grandmother realised she had acted wrongly and went upstairs to apologise to Antonio. When she opened his room door he was lying on his bed masturbating. She told Antonio that when he had finished his homework she would like a word with him.