The act of setting in motion a woman's breast or breasts in such a way that they will thereafter move on their own for the longest amount of time possible. This can be done without hands via genital to genital intercourse, anal intercourse, or irrumatio (facefucking), as well as by many other means. However, the best results, i.e. the longest handsfree bobbling achievable, can usually be achieved with the use of one or both hands and by giving the breast or breasts a healthy shove or slap in a direction perpendicular or diagonal to the force of gravity. When bobbling both boobies, it is most desirable to bobble them each in different directions or at different frequencies, to avoid the slightly less pleasing visual effect of boobies bobbling in a synchronized manner.
"My tits are sore from all the boobybobbling you've been giving me." - Boobybobble Baby