Don't SASS us, Justin! Mr. Bieber hangs out backstage before his STB set in 2012 This image appears in the gallery:32 MOST MEMORABLE #CapitalSTB Backstage Moments 13. Don't SASS us, Justin! Mr. Bieber hangs out backstage before his STB set in 2012 32 images See the full gallery: 32 MOST MEMORABLE #CapitalSTB Backstage Moments