"Collaborator" itself sometimes confuses people too. People likely think one class using another one should result in each class noting the other as a collaborator.
This initially involves background analysis to come up with suggestions for the different ways users may interact with the system.
Actually this is not the case. In Beck and Cunningham’s paper[1], they mentioned the collaborations among objects are not necessary to be symmetric.
The class doing the using should list the other as a collaborator but not the other way around.
Some people prefer the simpler term "helper" because this made the direction of help clear. This will reduce the confusion from the word "collaborator" itself.