When Harry was a baby, Sirius would always wink at him when he was annoying James or Remus. One day when Harry was playing a very exciting game of 'Poke and Runaway' with his dad, he made sure James slipped on a toy car. James looked up at his son, glasses askew, and the young Potter unmistakably winked. James immediately gave Harry to Lily and floo-ed to Sirius' to give him a piece of his mind about corrupting his child.
A/N sorry I'm going a bit wink mad :P