The main difference between a slider and curveball is the way that they move. Imagine your throwing a slider at a clock. It would go from 3 to 9. However, if you were to throw a curveball at a clock it would go from about 1:30 to 7:30.
A hanging curveball is a curveball that is thrown in a way that makes it easier to hit. A good example of one is a slow curveball that is thrown down the middle. If you get one of these babies thrown to you while your at the plate, swing at it. It is an easy pitch to crush for a dinger or at least a double.
With your hand
Grasp the dodge ball with your hand and pull your hand in so that the ball touches your wrist and your wrist is curved in. pull you arm back and launch it moving your body with it. it is very tricky. right here is the way but learn your style to throw it while you have your wrist in.
Throw yourself on top of them.
throw it in the trash
I assume by this you mean curveballs so these all the ways to throw different curveballs: Curveball: Grip the ball like a two-seam and then put your fingers off-center so they're on the right seam, then snap your wrist hard off to the side. This can be very damagaing to your elbow if you're not mature enough and if you throw to many of them, can still be damaging even if you're old enough. 12-6 Curveball: Take the curveball grip and then move the ball up so your fingers are on the right seam of the horseshoe. PRESET your wrist in a position as if you're throwing a football. Then come straight down. This is much more safe than a curveball although with your fingers off-center you will probably come off very slightly. I would still not recommend throwing it if your not old enough but you can most definetly throw it with hardly any risk once you're old enough to. Spike Curveball: Take a four-seam grip and then curl your fingers back so your fingertips are pressed hard into the ball. Then move your hand up so your about 3-4 of the way up from the bottom seam to the top and then throw straight down. It will have movement like a 12-6. Most pitchers have more success with a 12-6 but others have a better spike so you should definitley try it. This is completely safe to throw at ALL ages. Knuckle Curveball: Position your index and middle knuckles so that they're on the bottom of the horeshoe seam and the thumb underneath. As you release flick your fingers forward. This will have curveball-like movement and is safe to throw at ALL ages. However, it could seriously mess up your form so be careful of that.
The best way to disspose of it is to throw it in the trash in an oder proof bag.
Throw them up against a wall
Throw a masterball at it.
throw mud at it
The best way is to try and use a Pokemon with a status effector then just throw ultras at them.