First off: I think it is a natural male impulse to exploit weakness. However, it is not right. It is not morally acceptable. Behavior like that violates every social compact we have struggled to put together. It is, unequivocally, immoral. Second: whether right or wrong, this motherfucker is not going to back down, and he will continue to exploit your reticence to his own puerile advantage. You must beat him. Stuttering is bullshit. It’s unfair, it’s untimely, and it’s just fucking shit. So you have to win. You have to beat it. Ultimately this isn’t a battle between you and this arrogant sonuvabitch, it’s your battle. Advice from from someone who has stuttered his entire life: 1) When making a point, hold of your hand in a stop motion. You are speaking. No one else may speak. When you have thought, you conduct yourself as royalty. No. One. Else. May. Speak. 2) Listen attentively. Demonstrate that you are absorbing information, but not as a subordinate. You are in charge of the data you absorb. You have answers. 3) Finally, you may not feel confident. If you’re anything like me you feel insecure, small, and ignorant. Let no one know that. You are the commander of your space. You dictate what comes in and out. You are in charge. I know these points are cheap. They are much easier said than done. But when you stutter, the world gives you no free turns. You have to take by main force every opportunity. Be well, and keep fighting.