And don't say you don't have any, EVERYONE has stretchmarks. Not just from pregnancy but from general growth over the years.
Mine (from pregnancy) are vertically on the sides of my hips. I call them my claws, lol. I also have a couple faint ones on my tummy.
And I have some super faint ones on my butt from puberty or whatever, they've been there since I was 12/13.