Place bacon in a large skillet and cook over medium-high heat, turning occasionally, until evenly browned, about 10 minutes. Drain bacon slices on paper towels.
Combine mayonnaise and sour cream in a medium bowl. Crumble bacon into mayonnaise mixture; mix until combined. Stir in tomatoes right before serving.
Notes
You can reduce calories by using low-fat or fat-free ingredients. Serve cold with crackers or chips.