When a woman decides to take part in the act of masturbation. The "link" is the finger of the female and the "pink" is the vagina. The finger and the vagina link together/go inside each other. Thus creating a "Pink Link."
Families who have 2~4 children and a 1 pet in order to be showcased on the Happy Family sticker on their cars' rear windshields.
You can spot a Happy Family unit from a mile away; they always have that Happy Family sticker proudly displaying their two kids and a fluffy dog on the rear windshield of their cars!