Incest Is Wincest - Family Fun and Kin

The joke plays on the similarity between the words 'incest' and 'wincest,' suggesting that incest is a winning situation. It then goes on to say "fun for the whole family," which further emphasizes the incestuous theme, making it pretty shocking. It concludes by saying "next of kin, count me in," which implies the speaker is okay with it too.