Slang believed to have originated in the North of England, bird turding means to talk nonsense, or to boast with nothing to back it up. Possibly derived via pigeon fanciers, telling someone that they are bird turding means that they don't have the facts and are basically talking bird shit. Telling someone that they "ain't bird turding" means that they have got it right.
When a man washes or soaks his entire private area in a sink (usually a bathroom sink) in an attempt to get it clean. (This term was created and coined on the judges podcast - anchor.fm/the-judgies)