Can you get pregnant if a guys comes in you?

Yes, for sure: That is the way people have almost always done it. If you both are fertile and if it is the right time with respect to your ovulation - you'll have a very good chance of becoming pregnant. If you don't want to be pregnant, don't do that without protection. Seek information from a reliable source about human sexuality and procreation. It's important to know about what you are doing. Best!