[ shuǎ zuǐpí ]
"to show off with clever talk"
This phrase is quite simple and easy to use but definitely makes a point. 耍 means 'to play with' or 'to display' and 嘴皮 is a slightly derogatory way to refer to 'mouth/lips' resulting in the meaning of 'to brag'. You should be careful using this frame as it does carry a rather strong negative connotation - it should only ever be used in jest with close friends (who will see the joke!).
="That guy, he spends the day showing off but in reality, he has nothing".