This is directly related to something valuable I learned when I started coaching FP.
Many moons ago as a player I was taught a linear swing that (unfortunately) still comes naturally to me today. When I started hitting infield/outfield as a coach the typical bottom hand toss and swing with both hands naturally put me into the linear step and swing like Strike2 said above.
But, one day while I was trying to demonstrate a rotational swing vs a linear swing to a player, I decided to toss with my bottom hand and over-exaggerate the rotation of my body while pinning my top hand elbow to my gut, holding the bat with my top hand only, and keeping my wrist loose like a well-lubricated ball joint. Basically I was trying to show her you can hit the ball very hard with a strong body rotation and no arm input.
I liked the feeling of this one-handed swing so I started using it for all fungo work with a 32 inch bat (the 34 was a bit much). What surprised me is that I was eventually able to hit outfield balls with less effort and infield balls with much more control (backspin skippers, topspin bouncers, line drives, pop ups, etc.) than when I used a two handed swing.
And from that point on, when I spoke with a player about using their legs and core muscle groups to swing the bat, all I had to do was ask them if I used my arm to hit the ball during fungo. Most had not given it any thought, but when they did, they realized I was not using my arm at all to make the bat swing but instead was allowing the bat to swing while rotating my body. Not all players needed this visual but it did help a few. And a couple of them said they really got the feel of it when they decided to do the one-handed self toss during their turn to hit fungo at practice.
