FriendTracker

This app allows you to locate your friend on a map. You can keep a list of friends, and locate them on a map if they enable their location, or if you don't block or get blocked by them. As such, you can add/block/delete friends whenever you want.
To add a friend, you need to know his/her username. The add will be placed as a pending request for your friend.
You can forbid some of your friends from seeing you on a map by blocking them, or you can forbid all your friends altogether by setting the enable location button to off.