In order to make the helicopter rotor do what we want it to do, we have to create a dissymmetry of lift with the cyclic.
Flapback and inflow roll are the rotor flapping to equality because we have created an inequality, either in speed on one side of the disc or inflow angle between front and back.
In a transition to forward flight, if left to its own devices after an initial forward input, the rotor will pitch up and roll towards the advancing side - we prevent that happening with appropriate control inputs.
Flapback occurs throughout the flight envelope and is very noticeable when you change speed - inflow roll is most noticeable at lower speeds but still occurs when there is a difference in inflow angle between front and rear.
The rotor seeks to equalise lift, we seek to create an inequality to control the aircraft and make it go where we want.
Robbiee - the US military used the term blowback for many years to describe flapback,.and the FAA helicopter flying handbook uses exactly the same term.