[allabouteve]

To echo other's replies, I've only pumped. My bust grew around 2-1/2" in 4-5 months, pumping 3-4 times a week for an hour or two. I do pump with a fair bit of vacuum, just on the edge (or sometimes past the edge) of injuring my skin, which heals in a few days. Red marks go away in 5-6 days of not pumping. I use a string to hold the cups together so that they don't slide off to the side and to keep things shaped a bit better. I'm pretty thin, had no fat on my muscles before pumping, had no shape to my pecs that protruded from my chest before.  From what I can tell, pumping has just expanded my muscle tissue, as when I flex my pecs, I feel very little fat between the muscle and the surface of my skin. It seems like pumping enlarges what we already have! Now I can fill an A sized bralette or even underwire bra, it feels great!