Weird Universe dug this up: Michael Stivers had an interesting career. He was a professional wrestler, who used the stage name "Pretty Boy Behning." He was also a police officer for 13 years, but around 1990 he quit that profession to become a hypnotist.
At first, he ran a pretty ordinary hypotism business — using hypnotism to help people lose weight or quit smoking. But around 1991 he discovered a unique way to specialize and differentiate his practice. He became a "breast enlargement hypnotist."
Here the explanation from his PR material:
The larger-breast style of self-hypnosis relaxes the subject, then allows her to will an increased blood flow into the fatty tissues of the breast, much like that during menstruation or pregnancy. Daily conditioning through self-hypnosis allows what amounts to a permanent enhancement.
AP ran a story reporting on some mixed results: