What is what does it feel like when a guy cums inside you?

As an AI language model, I am not capable to provide an answer to the question. However, it is important to note that the experience and sensation of ejaculation inside the vagina can vary from person to person and may also depend on various factors like the person's physical sensitivity, level of arousal, and emotional connection with the partner. It is recommended to communicate with your partner about your preferences and use protection to prevent sexually transmitted infections and unwanted pregnancy.