How does Jem ask Scout to treat him at school… Why?

From the text:

"Jem was careful to explain that during school hours I was not to bother him, I was not to approach him with requests to enact a chapter of Tarzan and the Ant Men, to embarrass him with references to his private life, or tag along behind him at recess and noon. I was to stick with the first grade and he would stick with the fifth. In short, I was to leave him alone."

Why? Older siblings have no wish to have their younger siblings taggind along after them or embarrassing them. It's a kid thing! ;-)