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Finally... the pain thing... it is tough. I know from personal experience how tough it can be to hurt someone you love, even though they are enjoying it. I used to get really nervous about spanking because I was scared I was spanking too hard and that usually meant she was not enjoying it because it was not hard enough (pun unintentional there but left in because it fits

And there's another pun right there... I'll stop now...). In time you will learn to overcome that and be able to enjoy hurting him as much as he enjoys being hurt. One thing I might suggest - aftercare. Talking about it and hugging etc after a kinky act can help and make you feel more comfortable with it. Ask him if you hurt him too much, if he'd like you to hit harder or softer and so on.