Heat oven to 425ºF. Mix mayonnaise and 2 tablespoons Bisquick mix in medium bowl until well blended. Stir in turkey, cheese, celery and onions, set aside.
Mix 2 1/4 cups Bisquick mix, the milk and sage just until soft dough forms. Place on surface generously sprinkled with Bisquick mix; gently roll in Bisquick mix to coat. Knead gently 10 times. Roll 1/2 inch thick. Cut with 1 1/2-inch round cutter dipped in Bisquick mix. Place close together around edges of ungreased square pan, 9x9x2 inches.
Spoon turkey mixture into mound in center of biscuits. Bake uncovered 18 to 20 minutes or until biscuits are golden brown and salad is hot.