Being disrespectful in that way is very wrong and there is no excuse for it. Even if you do have low self esteem, simply tell him off, right in front of his friends when he does it. By the time you do it 2-3 times, he'll be so scared his mates will think hes a wally, he'll stop. But you have to be really firm about it, and even when he apologises, dont give him an inch even if you have forgiven him. Its the only way to sort boys out. =)