Another method that is better than what you have requested is shown below. Push one button the motor turns one way, push the other it goes the other way, push both and it stops.
The diodes absorb the inductive kick from the motor when it turns off. I know it as a bidirectional tranzorb, it is two high current zeners in one package. A MOV can also be used. A 25V rating would work. It is not absolutely necessary but will stop arcing across the relay contacts and make them last longer. There should be something across the relay coils as well. I would suggest a diode and a 470 ohm resistor in series.