Put 2 layers vanilla wafers on bottom of 3 quart oblong casserole dish. Mix pudding and milk. Mix sour cream with half of cool whip. Cut up bananas. Fold sour cream mixture and bananas into pudding. Pour over vanilla wafers. Top with remaining cool whip. May layer bananas and pudding if you like Also, sprinkle crushed vanilla wafers on top of Cool whip, if desired.