Reality star Brielle Biermann, 22, posted a sexy photo of herself wearing a thong bikini, showing off a good portion of her perfectly tanned butt. Biermann was modeling the sexy bikini from a swimsuit line from her mother’s, Kim Zolciak Biermann, upcoming swimwear line, Salty K. The “Tardy for the Party” star captioned the sexy ass picture, “Pool day,” View …