It's pretty obvious you aren't that close then, let alone "very close". That you haven't been invited over should be your clue that maybe the "close" relationship you think you have is a one-way street and your "very close friends" may think you're an acquaintance at best. Maybe your "very close friends" don't really enjoy your company and accordingly do NOT want you in their house. Maybe your "very close friends" roll their eyes behind your back when you attempt to use them with this "Some of My Best Friends Are Black" routine like you're doing now.