When two or more systems on a machine interfere with each other in a way that makes one or both of them do something very odd.
If every time you hit the brakes in your car the radio changes channels, your car has "cross mojination" between the radio and brakes.
The synergistic augmentation of Mojo that occurs when 2 or more people of high Mojo are near each other.
Whenever I get around Sarah, there is a serious Cross-Mojination effect. Stars align, seas calm and the whole of the cosmos watches as the magic unfolds. Then re-folds. Then unfolds again. And then re-folds.