So how to become master of the senses? Senses are very strong. How one can become master? The simple method is when one engages the senses in the service of the Supreme Lord, it is automatically controlled. It is automatically controlled. The senses want . . . just like your mind. If your mind is absorbed in certain subject, you cannot divert your mind to another subject. Sometimes, if your mind is engaged in some serious business, you are thinking, and some friend has come before you, you cannot see him. He asks you, "Mr. Such-and-such, don't you see me?" "Oh, you have come?"
That means the senses, the chief sense is the mind. If you can engage your mind to Kṛṣṇa, in the service of Kṛṣṇa—sa vai manaḥ kṛṣṇa padāravindayoḥ (SB 9.4.18)—then your senses are automatically controlled, because mind is the chief sense. Under the mind, all other senses, namely the eyes, the ears, the nose, the hands, the legs, they work. If one is absent-minded he cannot work nicely, because mind is absent, or not in order. Therefore our method of controlling the senses is to engage the senses in the service of the Lord.
The first engagement should be that mind should be always absorbed in thoughts of Kṛṣṇa. Always engaged.