I agree with the above poster. Many guys don't know how sensitive a woman is and how easily they can get scratched. He needs to wash his hands before he touches you to keep from getting an infection.
Another thing, many young people don't know each others bodies very well. Young men may think it feels good to be rough and to go as deep as they can with their fingers. If you feel any pain you need to tell him to be more gentle.
It's not suppose to. You might be scraching it with your nails. That is a sensitive area and must be handled differently. Trim your nails first and then see