Question:
Good morning, sir,
I’ve a question: When does the penis grow in length and girth? How do I know it has grown? Does it have stretch marks or any signs to show that it has grown? Is the growth before or after my growth spurt?
Answer:
Penile growth is most easily determined by measuring the length and circumference of your penis when you are fully erect. The growth in length begins in stage 2, but it changes the most during your growth spurt during stage 3. The growth in girth changes the most during stage 4, after your growth spurt slows down.
Since the skin on your penis shaft is loose and flexible, it would be unusual to have stretch marks on your penis.