Ok so hear me out. Due to gravitation time dilation, your upper body is technically older then your lower body, that is ofcourse ... due to Gravitational Time Dilation. Gravitational Time Dilation is the effect gravity has on time. The lower the gravitational potential, the faster time is. Knowing this, because your d ick has more gravitational potential then your head, your head is older then your d ick (by like less then a millionth of a nanosecond but that doesn’t matter). So if you were sucking your own d ick while you turned 18, your head would age first. This means your 18 year old head would be sucking you 17 year old d ick. and you're a pedophile. that's all i wanted to say ! Thank you for listening to my TED Talk.