So, if you don't have a quick-shifter in your motorcycle (like me) you can still shift w/out the clutch. You can ride a motorcycle or drive a car without a clutch, it would just suck alot, and you'd probably wreck the transmission pretty quick. All the clutch really does is ease the power transition from the engine to transmission, acts like lube. There is a point for every engine when they are both turning at the same rate, where neither is powering the other, its a small point that you can feel it, or do math and find it. That's when you can slam that gear up into place without worrying your gonna do (much) damage.
Motorcycle transmissions have gears! Specifically sequential gearboxes (most of the time). The Crankshaft has a gear! Low gears like 1,2 have many teeth while high gears like 5,6 have fewer teeth. These all get power from the Crankshaft gear (which the pistons drive) which has a fixed amount of teeth. Engine Power -> Transmission Power -> Rear Wheel. When you do a clutchless shift, you are SLAMMING that gear into place, there is no lube, bite the pillow, engine, I'm the transmission and I'm going in DRY. The engine then is then forced to move relative to how many teeth are on the gear being activated (or break). If you shift up, it'll drop, shift down, and it'll go up.
Sometimes they will line up perfectly and go in perfectlyanddamndoesitfeelgood, but most of the time they won't go together and just make a grinding noise. Slowing the engine speed down (pulling in the clutch) allows the transmission to fit into each gear easier, smoother, and in turn doesn't do any damage. When you let the clutch back out since it is turning slower it will mate with the gear better and then you can give it gas and make the fat bitch move.
Is that what you were asking?