The inner elbow is a strange and magical place. Preteens practice kissing it because it's soft as lips. Pick-up artists recommend kissing it, because it's a "sensual spot." And when you're a world-famous pop star struggling to maintain decorum after peeing into a mop bucket, the inner elbow may symbolize your conscience — or some externalized version of it. At least we think that's what Justin Bieber is doing with this tattoo of his mother's eye on his inner elbow. "Moms always watching ;)" he wrote on Instagram of his new Bang Bang–inked tat.