If you hold the ball pointing straight out in front of you lengths ways and kick it, it will go end over end. Now if you hold the ball sideways and kick it, more often than not you'll hit slightly off centre, one side or the other, and the ball won't go straight, it'll 'banana' to one side.
If you make it look like you're going to kick to your left, then kick the ball more to the left side of the centre of the ball, it will instead go out to the right.
There are many variations in how you hold the ball as to exactly what the reaction will be when you kick it, this is where a bit of practise will help
For example, the same theory works with grubber kicks, you can deliberately 'banana' the ball along the ground too...
coming from an AFL state and having no choice as a kid, the banana kick was a common part of the game.
obviously you'll need to go out in the paddock on your own for a few hours to get the 'feel' of it, however a few pointers:
hold the ball directly in front of you with the pointy ends in each hand. the pointy ends will be what you aim with. if your taget is on your left, line up the pointy part of the ball with your target and kick the ball towards the right hand point end. use the reverse if your kicking to a target on the right hand side. line up the right hand pointy end with your target, kick the left side of the ball.