We've found 5 phrases for Cooper (0.131 seconds):

hand in glove »    In very close cooperation.

hand-in-glove »    Closely cooperative.

it takes two to tango »    Some things need the active cooperation of two parties; blame is to be laid on both parties in a conflict.

knuckle under »    To yield or cooperate when pressured or forced to do so.

play ball »    To work together; to cooperate.

BTW, Why won't you become an editor?