did you enlist on the 16th of june?
speak to your pc?
First things first, this is not an abuse of authority since he never actually pulled rank or made you do something you didn't want to. Its more of personal humiliation. Such behaviour is not only childish but its also unprofessional and reflects badly on the uniform and rank.
Speak to him and let him know that he is humiliating you. If he refuse to stop, bring this matter to your PC or OC. The worse you should do is to lose your temper.
There's suppose to be an avenue of filing protests against such harrassment but I'm not too sure how it goes now, having been out of it for so long.
Try S1 or chief clerk's office.
http://armedforces.sgforums.com/forums/1390/topics/321263
pls continue in your thread.