Becci, the malevolent enabler. Have you noticed how Becci's stories oscillate between Sarah-focused posts, social causes, random polls and questions designed for followers to overshare. I think Becci gets followers to confess secrets so Sarah and Becci can laugh at them and feel superior. Sarah does the same thing when she's wasted and alone. Classic narc behavior.
She's definitely one of those people you can't bear to spend time with because they try SO DAMN HARD to be funny and self-deprecating but always just miss the mark.