Restrict a piece by attacking what is behind it.
A bishop, rook or queen can pin a piece to something behind it. A piece pinned to its king cannot legally expose the king to check. A piece pinned to a queen can move, but may lose the queen. Attack the pinned piece with a cheaper piece when the exchanges work.
Add pressure to the pinned knight
Your bishop pins the knight to the queen. Your other knight adds an attack. Moving the pinned knight off that diagonal would expose the queen.
2 more clean runs (at any point) to reach Recall.