A shoulder throw, or shoulder, is quite similar to a backcross, the main difference being that the club comes over the shoulder on the side from which it was thrown, rather than over the opposite shoulder:
Note that the clubs no longer rotate in the body plane as with backcrosses, but are now almost perpendicular to it.
Although more commonly done with balls, shoulder throws can produce some interesting effects when clubs are used. It is rare to see a solo club juggler doing this trick, it is usually reserved instead for club passing with a partner - probably because most people find it easier to send the throw forwards than upwards.
It is an awkward movement to send a shoulder throw over from one hand to the other, although it can be done; at first however, it is better to throw and catch it with the same hand. The clubs will travel straight up and down on one side of the body. To incorporate such a trick into a cascade it is probably best to use a double spin (for reasons of timing, throws to the same hand are usually doubles). Doing this on both sides produces a box-like pattern, with one club being thrown back and forth as a single, and the other two being thrown as double shoulders each time
In order to throw shoulders continuously in this manner you should first try juggling 2 in 1 hand, making each throw a double shoulder, introduce the third club and juggle in a staggered columns pattern. Each time you do a shoulder throw to the same hand, as described, try to bring your hand right up into your armpit before releasing the club, this gives you a reference point for the throw - if you throw from the same place each time, your throws are more likely to be consistent.
Hold the clubs right at the end, at the moment of release you should be gripping them lightly, by the knob only. Make the throws high and slow, there is very little wrist action necessary for this trick, the club's rotation comes mostly from the circular swinging action used to bring the club from the front of the body to the back. As you carry the club upwards towards the armpit, concentrate on lifting it straight up, ensuring that the club stays perpendicular to your body plane after it has been released. Don't hunch up your shoulders and neck when doing this, try to stay relaxed. Lastly, it is important that your throws travel forwards slightly as well as upwards, in order to avoid collisions and to aid catching. Catches are made at around eye-level, with the palm facing forwards and the club more or less horizontal, as shown:
If your throws go too far in front of you then try releasing them a fraction sooner, if they go too far behind you then you are probably throwing too early - hold onto the club a little longer before releasing it, in order to hook it forwards.
If you wish to try a shoulder throw cascade, where each club is thrown over to the opposite hand, rather than to the same one, then I would suggest you use doubles again - the higher the throw, the more gradual the crossing over will be. Angle the body of the club away from you a little, your hand doesn't go up into your armpit now, instead it should be lifted towards the centre of your upper arm. Also turn your shoulder into the throw to angle the club still more towards the other side. Aim to hit the central point of the pattern with each throw.