Here are some examples of how it's used:
* "The band's performance at the festival blew my socks off!"
* "The chef's new dessert was absolutely incredible - it really blew my socks off."
* "That new movie is going to blow your socks off - it's the best action film I've ever seen."
The origin of the idiom is unclear, but it's thought to have originated in the early 20th century.