When your own mother takes your erect penis in her hand and and guides it into her warm, wet, hairy vagina on your birthday and squeezes your balls with her hand and your penis with her vaginal muscles while you perform intercourse until you ejaculate internally and leave her a dripping wet creampie.
You will find most incest cases come from Indiana's very own Riverton Park. They have rich history of this act in all of their lands. Legends say, such as Abraham Lincoln, they've been doing since they were born.