“split your sides”正是“捧腹大笑；笑破肚皮；笑弯腰”。

【例句】
All the audience split their sides at his address.
听了他的讲演，所有听众都捧腹大笑。

We practically split our sides laughing/with laughter watching Peter trying to get the toy into the coat.
我们看到peter试图把玩具放进衣服里，几乎笑得直不起腰来。