G,
Not everyone is an engineer and you certainly don’t need that level of knowledge to enjoy flying as a private pilot.
Aft CG gives lower apparent static stability, lower manoeuver stability, generally less well damped short period longitudinal and lateral/directional static modes and Dutch Roll mode, it may well make the long period longitudinal mode better damped; the spiral mode is more complex because that is primarily dependent upon the RATIO of static lateral to directional stability.
This is certainly not an answer you should give an aspiring private pilot.
Its just meaningless gobblygook to them without any point of reference they can latch on to.
The instructor needs to teach to the level of the student.