twist是拧、扭曲的意思，arm是手臂、胳膊，twist someone's arm不能翻译成拧某人的胳膊，真实含义是给某人施加压力，迫使他做你要他做的事，说服某人。

【例句】
I didn't want see that movie about Mozart, but my roomate twisted my arm.
我本来不想去看那个有关莫扎特的电影的。可是，我同房间的同学硬逼着要我去。

You don't have to twist my arm. I told you I would go with you to the shop.
你不必逼迫我，我告诉过你我会一起去商店的。