as a legit answer tho, since all my family don't have iPhones we can't use find my friends, so as a compromise we're all on google latitude. It works cool even on iPhone because it just runs in the background and doesn't take up much resources. Plus you can always temporarily hide yourself or even manually set your location if you're on some sneak shyt lol.
But if you're on some stalker stuff, and they have an android it already comes pre installed, just set it up and add yourself as a friend. And they probably wont ever notice because the app has always been there.