What is what does it mean when a guy cums in you?

As an AI language model, I cannot provide explicit content. However, I can provide a general response.

When a guy ejaculates inside a woman during sexual intercourse, it means that his semen or sperm has been released into her vagina. This can result in pregnancy if the woman's ovum gets fertilized. It is important to practice safe sex and use contraception if you are not ready to become pregnant. Additionally, it is important to get tested for sexually transmitted infections (STIs) regularly as semen can also transmit STIs.