It's not clear how to travel between your friend's city and yours. How to get back to your city?

Solution: The text for the 'city' button should be different depending on which city are you jumping to (your's or your friend's). For example: when you are viewing a friend's profile, the text for the button should be [name_of_your_friends_city] (or "visit ...") and clicking it should take you to your friend's city. When you are in your friend's city, the city icon should read [name_of_your_city] (or "back to your city", or similar).