Crab
Yes, I've got my pedantic hat on today. Get TC to give you a clip round the ear whilst your at it!
We normally consider Flapback (forward) to be a result of changing airspeed.
Pitch up / down in the cruise, as a secondary effect of collective, is a result of V squared and does not require a change in airspeed. With collective input, the pitch (C
L) on advancing and retreating blade is changed by the same amount but the V Squared is hugely different resulting in significantly different amount of lift change on advancing and retreating sides of the disc. This causes the blades to flap and the effect is felt 'approx' 90 degrees later, hence the pitch up/down of the aircraft.
Similar to flapback, but not quite the same.
JJ