this is serious, im not joking. Are you trying to fuck her? If you are not trying to fuck her then be brutal. Pull a Marlin Pie and stare at her with a stupid face and make fun of her for losing to someone who isn't even looking at the screen. If you are trying to fuck her, then be sweet and offer to buy lunch if she can go an entire match without mashing. Other trick to do is limit yourself to only throwing and limit her to only using 1 button. If she can only push one button and she knows you are not going to do anything other than throwing, she may be more likely to relax and not mash.