Under what circumstances can a man with ten fingers count eleven?

There is a joke like this. When Xiao Ming is in math class, the teacher asks him to count his fingers, but he has the habit of putting them in his trouser pocket before counting. When he puts his hands down, count them and report to the teacher eleven times! The teacher was puzzled and said, Wrong input, counting from the number, Xiao Ming counted again, still eleven. The teacher was very angry and asked to say it again. It was wrong. Xiao Ming counted carefully one by one, but still eleven! Because I counted my dick.