You will read comments which use the words adverse and proverse --roll couple
as noted these are simply words describing which way the rudder application affects the model
ADVERSE - just like the word is typically used --means against -
left rudder rolls the plane right
PROVERSE - the rudder causes rolls in same direction as it is moved.
On a good aerobatic setup --there is a hint of adverse roll -just a hint
We put this feature into most of our aerobatic designs -- so that when doing an extended slow roll -- more rudder could be added --without causing the roll to speed up
The roll couple will also change from design to design and may also only occur with high deflections
a secondary effect is that pitch is affected on hard rudder application - so---it is very possible to have a setup where the rudder application reacts as follows:
yaw then roll then pitch- it gets spooky .
got it?