How to use "speaking of which"?

[Bangkeaw]

Hi everyone!

This is my second post of today! So..please pardon me for my over-curiosity about English..

Might I ask for 1) the meaning of "speaking of which? , and 2) in what context/situation it can be used? (a sentence example will be very much appreciated)

Thank you very much (:

[Conchita]

'Speaking of which' can be used to refer to something that has just been said. Other similar phrases are: by the way, incidentally, apropos, with regard to...:

I won't be home when you get in from school tonight. Speaking of which, don't forget your keys.

[Bangkeaw]

Thank you very much Conchita! Your answer was very clear... crystal!!!