The Winky P is the epitome of flirtatious action over text. It is the perfect combination of a winky face and a teasing :P face bred by the gods themselves. It is not meant to be used in every day situations, only when you really want to display your extreme desire to bed the other person.
A text example:
Jack: Hey Chrissy, girl you should come see me more often ;P
Chrissy: Haha oh you think so? That winky P was really sexy, of course I will!