The last few times my girlfriend and I have had sex, she's complained about interior abdominal pain afterward... Last time it lasted 2 days and it made me feel pretty bad. She's a tiny girl and I'm, according to her, "Built for larger models"... But we're still very playful despite our problem. I've tried being as extremely gentle as I possibly can with her, I've toned it down a lot... And during sex she doesn't complain a bit, even suggests rough play, but afterward the result is abdominal pain. We plan on having her hold onto me, preventing me from fully entering her... But that just seems terribly uncomfortable for her. Suggestions? I was thinking maybe a cock ring or something to cut off how far I can penetrate might be the answer?