My bf keeps. scratching his private parts there is no rash hes not sweating no jock rash what could this be please help his scratching is anoying?

Bad habit?: Have you asked him if something is itching? If so, anti-itch products are available. It may just be a bad habit, which would require gentle re-programming to break it. Usually it takes a month to break a bad habit. Good luck.

New or habit?: If he always does this, it may simply be a bad habit. If he is getting sweaty in his "private area" and having an itchy area where his scrotum meets his groin area, he could be re-adjusting himself due to the skin of both parts sticking to each other. Have him try powdering the area and see if that helps, otherwise, a dr. can check him for a rash you may not have noticed. Best wishes.

Scratching crotch : Sometimes it is just habitual behavior. Male identity. But look for poor hygiene issues such as body louse. Trimmed pubic hair may not be so radical solution. Look for subtle signs of redness, rash or bug bites or jock itch (tinea curaris)