How about this explanation then:
The coning angle is the resultant of two forces - the lifting force, or total rotor lift, which acts at 90 degrees to the length of the blade (not at 90 degrees to the tip path plane - it is tilted a bit towards the middle of the disc), making the coning angle move up; and
The centrifugal force generated by the blade spinning around, acting through the centre of gravity of the blade, and trying to pull the blade outwards in the same plane as the plane of rotation, making the coning angle flatten out.
Add these 2 vectors together, and the resultant acts along the length of the blade, pointing upwards from the tip path plane/plane of rotation.
So, if you make one force bigger than the other, one vector will be predominant. Increase the RRPM, the centrifugal force gets bigger, and the blades will tend to flatten out. Increase the lift (more pitch/power) and the blades will cone upwards.
Heavy helicopters have big coning angles, little light ones have flatter coning angles.
Now we get to your question: apply aft cyclic, the blades cone up.
When in forward flight, and you pull back on the cyclic, you are rapidly changing the angle of the relative airflow - it now comes in more from below the blade disc, so it opposes induced flow, increases the angle of attack, the lift goes up, and the blades cone up.
But now another effect comes in - conservation of angular momentum. The energy of the blades spinning is now in a smaller total disc area, so the blades will spin faster. This increases the centrifugal force, and tries to flatten out the coning angle. Therefore, initially when you apply aft cyclic, the RRPM will increase as the aircraft pitches upwards, and it should stabilise with the new balance between rotor lift (which is now tilted more towards the mast instead of upwards, and is less effective) and increased RRPM, trying to flatten the blades out again.
It depends on how long you leave the cyclic input in place. If you started straight and level, you will very soon release the back stick when you see the attitude out the front, and your instructor will be turning pale as he recalls the effects of poking the nose over to fix the attitude.
However, if you are in a turn and increase the back stick, the effect will remain for as long as the pitching moment is there and you keep on turning. That is why the RRPM go up in a turn, especially when in autorotation, and you need to control the revs with more collective.