During male orgasm, the smooth muscle of the penis must contract with sufficient force to ejaculate semen from the penis.
Is the mean velocity of ejaculation known? I do not find scientific sources. I only found 17 km/h in the media without further elaboration.
Moreover, in some species, males must compete with other males for egg fertilisation. Presumably, evolutionary forces would favour those who had a greater ejaculation velocity. Is there a relationship between the velocity of male ejaculation and fertility?