一群朋友一起出去吃饭，最尴尬的情况莫过于到了结账的时候谁也不主动，一个个都变成了“鳄鱼的短胳膊”，够不着钱包啦。英语表达就是crocodile arms。

When going out with peers to a bar or restaurant and nobody offers to pay the bill, hence they and yourself have the short arms of a crocodile.
你和同伴们去酒吧或饭馆，却没有一个人主动买单，这就是你们这帮人都在装“鳄鱼的短胳膊”。

Example:
It's kind of a turn off when you go on a date with a girl and you got crocodile arms all night.
你跟一个女孩约会，却整晚磨磨唧唧不说买单，这意思差不多就是不想跟人家谈了。