On a semi-serious, related note, I used to be into serious strength/body building. As in, trained three times a day, six days a week. I'm well qualified in it too and was a personal trainer specializing in athletic and martial arts specific training. That was all in a previous life, these days I'm fat and lazy*.
I used to use a technique called visualization, augmented with static tensioning/flexing and, well, just 'feeling' myself. Visualization is a fancy way of saying, "imagine your biceps are really big, and the body will respond and grow them more". It's a bit more than just imagining, but you get the point.
You might be skeptical, but I'm convinced that it worked, enough that I did it for several years. I'm certainly not one to believe in 'quack' theories or wasting my time. I could actually measure the difference, and I hadn't changed my weight training routines.
A similar technique could be applied to anything the body can grow, I think. Breast tissue included. It does take persistence and faith though.
*Fat and lazy even though I do still own my own Versaclimber LX, possibly one of the most intense combined cardio/muscular exercise machines ever devised. It's currently in the front room, being used to hang hats on.