Does black call the shots?

Yesterday, I went to the chess club at UCD; being a part time grad student has its pluses.  Anyway, at chess club I got worked which was good and bad.  Good because I learned lot, bad because I'm just not that strong a chess player.  We ended up running through some lines, studying the Sicilian.  It was great but one of the people there who is seriously good and a great teacher said, "Black calls the shots."  Really?! I'm hesitant to argue because he's so good however, knowing something without knowing the reasoning behind it is pretty worthless.  I think it could be either white or black that calls the shots depending on the strength of the player.  So, who do you think calls the shots?