The appearance of the penis will change with your son’s body shape.
Newborns are often thin and have little fat over the pubic bone. They quickly become good at eating and develop substantial fat deposits, often over the pubic bone, in which case the fat pushes the skin forward along the penis giving it a buried appearance. This buried appearance usually goes when the rest of the puppy fat does, at around four years of age.
If the penis becomes buried, ensure the penis is ‘popped out’ with each nappy change for cleaning.