To talk shop

Idiom: To talk shop 


Read the following e-mail and try to guess the meaning of the idiom in bold:

Hi George,

How have you been?
I just wanted to thank you for giving me advice regarding my new job at LS. I know it was your brother's wedding party, and you probably didn't want to talk about work there, but all the advice you gave me was very helpful! I would never talk shop at my brother's wedding! You rock!

Thanks again!

Bob. 

Meaning: To talk about someone's job or business matters on a social setting.