Wipped Cream is normally used in situations requiring more than a simple "peace" gesture, so you normally wouldn't just use it to say goodbye to your friends (but you can if you'd like).
Whipped Cream is always supposed to be followed with a "Ya HEARD!" from a seperate (possibly random) person. Wipped Cream is also normally followed with "BITCH!", as "BITCH!" makes a great complement to any phrase.
While "Flashing the Whipped Cream" (what it is called to use wipped cream in action) one can also flash the "three finger salute". This is to is to hold up your index, middle and ring finger in the shape of a sideways W, and pivot your rist up and down.
The most common use of the proverbial wipped cream is in racing related activities.
-Kris is street racing Paul. When Kris blasts passed pauls slow POS, he sticks his head out the window and yells "WHIPPED CREAM!!" while flashing the "three finger salute". The homeless man walking up the street next to the race then yells out "YA HEARD!!!"
Another example would be during the break up of a girlfriend.
Mike is having an argument with his girlfriend. After some harsh words, she says "well maybe you should just go". Mike takes her advice and flashes the W/C by yelling WHIPPED CREAM BITCH!!!! in her face while throwing the "three finger salute". At this time, the girls father walks out (seemingly from out of nowhere) and begins flashing the three finger salute at his daughter while screaming "YA HEARD!!!!".