When choosing a male dog diaper, consider the following factors to ensure a proper fit and functionality: 

1. Size: Measure your dog's waist to ensure the dog diaper will fit comfortably. Most brands provide size guidelines based on waist measurements. 

2. Absorbency: Consider your dog's needs. If your dog is dealing with urinary incontinence or is in the process of being trained, choose a diaper with appropriate absorbency. 

3. Comfort: Look for diapers with adjustable closures and breathable materials to ensure your dog's comfort. 

4. Leak protection: Choose a diaper with leak-proof barriers to prevent accidents from causing messes. 

5. Durability: Select a dog diaper made from durable materials that can withstand your dog's activities. By considering these factors, you can choose a male dog diaper that will suit your dog's needs and provide comfort and protection.