make an ass of yourself 做蠢事，出洋相，闹笑话

【例句】
Please don't! You'll just make an ass of yourself.
千万不要啊，求你了！你只会让自己当众出洋相。

Simon always makes a complete ass of himself when he's had too much to drink.
西蒙总是酒一喝多就丑态百出。