sentence: A man wearing a black vest holds white disc's in his hand while a border collie stands in front of him. sentence:  The man steps froward and slaps the white discs on his thigh. sentence:  The man steps forward switching each foot as the boarder collie runs between the mans legs. sentence:  The man taps his head with the white disc he crouches and the boarder collie jumps on his back and balances their. sentence:  The man tosses the the disc over his head and the boarder collie catches it and runs off.