吹牛皮

他又在吹牛皮了，別相信他說的話。

He's bragging again, don't believe what he says.

吹牛皮不用打草稿。

Bragging doesn't require a script. (It's easy to make up stories)

他說他認識很多名人，我覺得他在吹牛皮。

He says he knows many celebrities, I think he's just boasting.