Technically, men’s sperm takes some time between three days to two weeks as it travels up from the testees to the seminal vesicles, and before that it takes something like 72 days for sperm to be made in the testees via spermatogenesis (although this process is constant regardless of number of ejaculations), meaning that while technically a man could impregnate 9 women a day, realistically a man couldn’t because after the first few their viable sperm count would drastically falter.