kungeln — to settle something in a secret arrangement. Duden marks it as colloquial and derogatory. One of its examples is um Posten kungeln, to bargain secretly over posts.
die Kungelei — secret dealing
der Alleingang — the solo walk. Duden: acting on one’s own strength while doing without, often deliberately, the help or consent of others, as in ein nationaler Alleingang. In football the same word means a solo run by one player with the ball.
sich abstimmen — to coordinate with each other
Rücksprache halten — to check back with someone before acting