Twin flame, soulmate, sister from another mister, or brother from another mother — there are many ways to refer to someone you have a special connection with. You know how it's believed that people with moles, birthmarks, or scars that look similar (even identical) in the same spot may have a special relationship across lifetimes? Well, suppose you and your bosom buddy weren't born with matching birthmarks (very likely). In that case, there is another way to mark your special relationship, and that is by getting matching best friend tattoos!