The closest usage of sich fassen I have found is Fassen Sie sich kurz translated into Be brief.
But in my case (it's from an online german course):
Fassen Sie sich zusammen, meine Dame!
is translated into Try to compose yourself, m'lady! I don't even understand the English translation.
Could you tell me what is the meaning behind this expression sich zusammenfassen?
Update: It's one of the course at Memrise.com. But there are several courses