when bleeding the brake system one wheel at a time. one person pushes the pedal the second person opens then closes the bleed valve. person one lets the pedal up. repeat the process all over until clear fluid comes out.
The method I have used for many years to buddy bleed a hydraulic brake system is to first find out if your system is front/rear split or diagonal split. Most rear wheel drive cars are front/rear split and front wheel drive cars are diagonal split. Verify that the master cylinder is full and have the person in the vehicle pump the brake pedal slowly 5x and hold it down halfway on the fifth pump. Open the bleeder screw furthest away from the master cylinder until the fluid escapes. Due this several times until a steady stream of clear fluid escapes without any popping or evidence of air bubbles. After each opening of the bleeder screw, immediately close it and have the person in the vehicle pump 5 more times, hold the pedal half way down and open the bleeder screw again to achieve the desired results. One should ideally use a brake bleeder wrench, a tubing wrench or box wrench to open/close the bleeder valve. If the system is a front/rear split, the bleeding sequence is RR/LR/RF/LF. If it is diagonal split, the sequence is RR/LF/LR/RF. Some vehicles with ABS will require a scan tool to actuate the ABS unit in order to move entrapped fluid through the hydraulic portion of the ABS unit. Also, only use the factory recommended fluid in the system. I would imagine that smart cars would use DOT 4 or a DOT3/4 brake fluid. It is a lot easier to use a vacuum bleeder or brake bleeder kit that contains a reservoir to collect the purged fluid so it is not all over the brake backing plates & on the ground. Eye protection should be worn as well & it is also a good idea to keep your mouth closed while performing this procedure.