Advanced Ultimate Throws
 

The Hammer
The grip is essentially the same as for the forehand.
 
The significant difference is that the hammer throw is released upside-down, so that support underneath the disc is not as important as for the forehand. A tight grip with the thumb is important, since it is the digit which is doing the supporting. This makes the power and hybrid grips the better choices for the hammer. The harder the disc is thrown, or the more wind you throw into, the more vertical the disc should be when released. [2]

Air Bounce
When an airbounce is thrown correctly, the disk leaves your hand, approaches the ground at a point a short distance in front of you, and then mysteriously rises. When I throw, I keep this in mind. As near as I can figure one of two things is happening when you make this throw. First, look at it like you are taking a huge trashcan lid and compressing a whole lot of air, between it and the ground, and this compressed air, then expands, and propels your disc back upwards.
Second, view your disc as an air plane wing that has it's front edge tipped upwards so that as air passes under its surface, it has the tendency to get lift and rise.
When you make your throw:
1. Use your thumb to push the rear of the disc down, leaving the front edge slightly higher and allowing for the airplane wing lift effect. As your arm propels the disc forward, this angle will give it lift.
2. Standing sideways with your Right foot out in front, toward your catcher and maintaining the disc angle with your thumb, start your (right handed) throw, high up near your left shoulder. Now, using your thumb to keep the disc angled up, sweep your hand and arm down (diagonal motion) low toward your right knee and out to an imaginary point about 4 to 7 feet in front of you. (place another disc in front of you as a target if necessary.) This motion needs to be fast, so that you compress the air, instead of just "fanning" it out of the way, the way you would fan yourself on a hot day. By moving downward quickly, you will compress the air you need to get a good "bounce" off it. Hence the term "Air bounce"
You have been told to push hard with your thumb. You need to push with your thumb to keep the tail of the disc down as you compress air. I often start with my disc 45 to 65 degrees up from horizontal and often nearing vertical, This allows me to grab a lot of air and then I flatten out to more like 30 degrees as I release. Your friends have been trying to tell you to use that thumb to create pressure and air compression as you try to shrink a square foot column standing air 3 to 4 feet high into a 1' by 1' by 1' layer of air that the Frisbee can ride up on.
A good air bounce can be thrown under a park bench and come out the other side rising. I have heard urban legends about greats who can put one under a car and have it float back up to catchable height.

Wrist Hammer (Scoober, Scooper)
This throw uses a standard backhand grip. The disc is flipped over so that the dome of the disc is resting on the wrist and forearm. The throw is from the forehand side. The disc is brought back towards the shoulder and then thrown forwards at an angle of about 50 degrees. The flight path is the reverse of a normal hammer.

Thumb Hammer (Thumber)
This throw uses a reverse grip. The thumb is inside the lip of the disc, the outside edge of the thumb (the side away from the fingers) is pushed against the disc and the fingers are supporting the dome, but the grip is fairly loose. The throw is from the forehand side. The disc is brought back towards the shoulder and then thrown forwards at an angle of about 50 degrees. There needs to be a good amount of spin to get the disc to fly properly. The flight path is the reverse of the hammer.

Inverse Thumb Backhand (Snake)
This throw uses a backhand grip with the disc held upside-down. The thumb is inside the disc, with the inside edge of the thumb (the side closest to the fingers) pushed against the rim, and the fingers are curled against the dome. The throw is from the backhand side. The disc is brought back towards the shoulder and then thrown forwards at an angle of about 45 degrees. The flight path is similar to a hammer, although it tends to fly at a low height, and it will usually fade towards the backhand side at the end of its flight.

Bowler
This throw uses a backhand grip. The throwing motion is similar to bowling a cricket ball. The arm is brought over the shoulder with the thumb and forefinger leading. The disc is near vertical. A large amount of spin needs to be given to the disc as it is released, and the throw follows the reverse of a hammer flight path.

Thumb Forehand (Thumber)
There are a couple of different grips for this throw. The disc is the right way up, and the outside edge or pad of the thumb is against the rim. The palm is facing up and the fingers are curled onto the dome, although one version has the index finger inside the rim as well. The throw is from the forehand side of the body, and the action and flight path is identical to that of a forehand. Another variant on this throw starts with the disc held out in front, fingers facing forwards on top of the dome, and thumb facing forwards underneath. The disc is then whirled around the thumb (anti-clockwise from top for right-handers) and projected forwards at the right moment.

Thumb Backhand
The grip for this throw has the pad of the thumb inside the rim and the index finger along the outside edge of the rim. The throw is from the backhand side of the body. The disc is brought back flat across the chest and then thrown forwards. Lots of flick is required at the moment of release to get the disc to fly straight.
This throw can also be thrown from very low, both straight and as an air bounce, and from above shoulder height. Only the angle of the wrist at release need change.

Overhand Thumb Forehand (Discus)
The grip for this throw has the inside edge of the thumb against the inside of the rim, the index finger along the outside of the rim, and the remaining fingers flat on the dome of the disc. The throw is from the forehand side, and is released at or above shoulder height. The disc flies the right way up. The wind-up is again similar to a bowling action in cricket, with the disc is brought back upside-down at about waist height, the arm looping around and releasing the disc the right way up above the shoulder. The wrist needs to be cocked in such a way that the outside edge of the disc stays down, and so that plenty of spin is imparted to the disc on release.

Quick Release Throws
A by-product of having good wrist-snap is that you will find you are able to release throws with very little arm motion. The quick release throws are very difficult for a marker to stop.

High Release Throws
Quick release throws and high throws are very similar in technique, basically because you cannot wind up for high release throws. These allow you to throw over the mark, and often are unblockable because they are released so far forward.

Outside In (OI) Throw
In the case of a backhand throw, the disc starts to the left and curves to the right. Most OI backhand throws will be for people cutting from the middle of the field to your left, and you want the disc to curve into them. Also, if there is a defender halfway between you and your receiver, this is the throw that will get it around that defender. The disc is released with an inward tilt to achieve the OI curvature. In the forehand case the disc curves from right to left.

Inside Out (IO) Throw
For a backhand throw, the disc starts to the right and curves to the left. This can be used to throw to the right side of the field when the marker is trying to force you to the left (i.e. the forced side). Most IO backhand throws will be for people cutting from the middle of the field to your right (i.e. the break force side). The disc is released with a downward tilt to achieve the IO curvature. In the forehand case the disc curves from left to right.

Outside In (OI) Huck
When most intermediate players huck they tend to release as an inside-out throw to allow the disc to flatten out in flight. This is particularly true for forehand hucks. An inside-out is generally a difficult throw to complete because it needs to be released close to the body (easy to point block) and tends to float at the end of its flight path.
The outside-in huck, on the other hand has the following advantages:
 
Very fast, arcing flightCurves around intervening defendersCurves in toward the receiverCan be released out very wideShorter wind-upThe outside-in huck requires a lot of upper body energy to be imparted over a short time, it is usually a fairly stunted motion. It also requires a lot of wrist snap to keep its flight level and counter the natural tendency to turn over. Accuracy in release is also important because there is little room for error (the disc simply goes to ground if it misses its mark), and subtle differences in the angle-of-release result in very different flight paths. The only way to learn is practice!