A combination of the words "man" and "boobs" result being Moobs.
Usually sported by fat, overweight blokes or men who have attempted a sex change.
During the mating ritual it is not uncommon for a man with sizable moobs to seek and reafirm his alpha male status by vigorously jiggling his man boobs. As his moobs oscillate, swinging back and forth with a steady, uninterrupted rhythm they begin to resonate at arround 20,000 hertz approx. This warns off any other males that fancy their chances with his mate (as in female, not as in mucker, "pal" or bezzer cause that's just wrong).