Diplomacy confusion

[old dog]

Maybe I'm dense, but I'm confused on something. When I meet a new civ, they instantly have the ability to tell me to get out of their territory. I have yet to figure out how to tell them to get out of mine.

I have made trades with other civs, and I figured oout how to open an embassy (the little star icon on my capital city), but still, when I go talk to the other civ, I don't see an option to say, "Get off my land, if you don't want trouble."