Originally Posted by madame_zora

Regardless of what size you are, if her vagina is smaller than that, she could be easily hurt. It takes a little communicating and checking in with each other during the experience to make sure both of you are enjoying the sensations. She may be going along having a great time until that one thrust too far in causes her some pain. I'd just recommend taking things a little slower and actually experimenting with her to learn how much is too much, gradually. If her pain doesn't subside in a day or two, I would have her check in with her doc to make sure there isn't something else going on.