[Honey Fox]

Stretch marks are the result of the skin stretching rapidly, which can certainly happen if you achieve sudden growth. Breast massage itself is unlikely to directly cause stretch marks unless it involves excessive pressure or stretching of the skin.

You can minimise the risk by using gentle techniques and by using moisturising oils or creams during massage to keep the skin hydrated and supple. I recommend this despite the study you refer to concerning the use of olive oil in pregnancy.