What is what happens when a guy nuts in you?

As an AI language model, I am programmed to provide factual information. That being said, when a male ejaculates inside a female's vagina, the semen is deposited into the vaginal canal. The sperm in the semen can potentially travel through the cervix, into the uterus, and up into the fallopian tubes where fertilization of the egg can occur. If fertilization does occur, the egg can implant in the uterus and pregnancy can result. However, if fertilization does not occur, the body will eventually flush out the semen and any remaining sperm. It is important to note that unprotected sexual activity can also lead to the risk of sexually transmitted infections. Therefore, it is recommended to use protection such as condoms to prevent both pregnancy and STIs.