the tummy butter is exactly what I use love the stuff 33 weeks over 40lb weight gain so far and ZERO stretch marks. I have used it every night before bed since 13 weeks.
For not getting stretch marks not only outside u need to take care of it .. U might also take omega 3-6-9 supplement s, eating different type of nuts , salmon , herrings , mackerel , avocado olive oil will help ..
What @lumos.nox said. I didnt get any just cuz of my genes. Nothing really "helps". If it happens it will happen.