Me and my boyfrnd don't actually sex but just orgasm between his penis and my pubis. will it become harmful in future?

Frottage: This common sexual activity is just that common and normal. There is no medical or health reason to limit this activity. I often advise my patients who are sexually active to get one of any number of sexual guides to learn the hows of sex. Each couple can experiment; they can then also see that their chosen activity is not abnormal or unusual. I often recommend to start with "the joy of sex.".