The fungo is used by a coach to hit balls for defense practice. It is lighter weight, so less fatiguing to hit ball after ball. The fungo sheds its weight above the hands. The severely tapered barrel to drops weight and maintains a high moment of inertia. While the bat would be at greater risk of breaking if used in a live batting exercise, it is safe to use in practice because there are much fewer mis-hits.
First base fungo hits fly balls to center field (helps here if both fungo hitters move up and apart, hitting from about the front of the mound extended towards the bases). Center throws to second, second baseman is cutoff (for us it was, anyways - change to suit your style). Third base fungo hits balls to left field, who throw to third, with a second shortstop as cutoff (but you really don't need one, if you're shorthanded).
On June 17, 1890, Emile Kinst patented the ball-bat, or banana bat. The bat is shaped with a curve, hence the name banana bat. The creator of the bat, Kinst wrote: "The object of my invention is to provide a ball-bat which shall produce a rotary or spinning motion of the ball in its flight to a higher degree than is possible with any present known form of ball-bat, and thus to make it more difficult to catch the ball, or if caught, to hold it, and thus further to modify the conditions of the game".
Even in those formative years, authorities on the game warned the practice of hitting fungoes should be limited to coaches. Henry Chadwick, one of baseball’s earliest proponents, claimed “The weakest batting is shown when the batsmen indulges in fungo hitting,” according to the Art of Batting. Others agreed that the practice was bad for training a batter’s reflexes: “While watching some of our freshmen practicing ‘fungo’ batting the other afternoon it occurred to me that it was about the worst kind of practice a batsman could imagine in training his eye in batting,” a writer claimed in the March 3, 1886 edition of The Sporting Life. “It trains the eye to meet the ball in batting it in a manner which never occurs in actual play. It ought to be prohibited on every well regulated ball field.”