Well, according to the biological literature, "During copulation, the genitalia of certain males may elicit more favorable female responses through superior mechanical or stimulatory interaction with the female reproductive tract."
好吧，根据一些生物学方面的专著 “在交配过程中 通过一些机械的或是刺激性的交互作用 一些雄性的生殖器会运用雌性生殖系统 使她们产生更为愉悦的反应。”