Grrr! Thag no let you do TECHNIQUE! Grrr!
Personally I've been lucky to never have to train with somebody who tried to overpower (although my partners and I do play with muscle power here and there to highlight mistakes) and insult me at the same time, but I know this works well:
Tell Sensei you're just not getting it right at the moment (because you don't know how to deal with your partners strength) and ask him to show you. If he uses your partner, enjoy the show, if Sensei uses you, it helps you focus on the technique and ignore the schmuck. The four teachers I've had a chance to learn with were all good about knowing what the above request means and watching more carefully afterwards.