Hover offset is not a mode ... it's just how the tail rotor is built. Basically, if the t/r slider is center in it's range of motion ... the linkage to the blade grips produce a tail rotor pitch offset. So all things being centered (stick, trim, subtrim, servo, slider), the "built in" offset between the slider and blade grips will produce hover pitch on the tail rotor.
This hover offset is always there.

If you have an electric motor on the tail rotor then the speed of the motor will change your t/r thrust, but the principle is the same ... generate an equal and opposite thrust to counter whatever your torque value is.

When you move the stick/servo/motor controller (or the gyro moves the servo/motor conmtroller), the resultant pitch/RPM change is always the input + hover offset/hover RPM.

Actually YAW is in either direction, however, YAW produced by torque will be in one direction ... opposite the direction of the main rotor rotation. So a right rotating main rotor will generate a left nose YAW. The hover offset is designed to produce an equal and opposite force (right nose YAW). If everything balances out, you will hold the nose with no YAWing.

Good Luck,
d.tipton