penis sperm ejaculation into vagina

In other words, the repeated thrusting men do during sex could function to displace other men’s semen, before they ejaculate. Zietsch suspects penis shape could affect sex duration in bed. In a 2003 study, using artificial vaginas, artificial penises, and artificial sperm (corn syrup), researchers found the ridge around the head of the penis is able to scoop out pre-existing syrup from the vagina.