With nearly 2 million followers, Jen Selter has clearly earned the title of “Most Popular Ass on Instagram.” But as is life, there’s always a challenger squatting in the wings waiting to take her title. Like Alexandra Bring, for instance. She only has 200k followers but that hasn’t stopped her from posting pictures of her six-pack and Selter-esque ass. I’ll just be sitting here waiting for the inevitable ass-off.