If you have got time, spare time, simply chant Hare Kṛṣṇa, Hare Kṛṣṇa, Kṛṣṇa Kṛṣṇa, Hare Hare/ Hare Rāma, Hare Rāma . . . that should be your business. This is tapasya. Tendency is to crow, to make vibration like these frogs. That is our tendency. Because we are also conditioned soul, and the frogs, or any animal, they are also conditioned soul, conditioned by the material nature. Therefore tapasya, austerity, is required to nullify, to counteract this conditional state of living. Now we are conditioned. Janma-mṛtyu-jarā-vyādhi-duḥkha-doṣānudarśanam (BG 13.9). We are conditioned by these four principles: birth, death, old age and disease. This is our condition. The scientist rascals, they are trying to improve the condition of living, but what is the improvement? There is death, there is birth, there is old age and there is disease. No improvement. If you want to improve your condition, if you want to come back to original constitutional position, then tapasya. Then you require to undergo austerity.
Tapo divyaṁ yena śuddhyet sattvaṁ yato brahma-saukhyam anantam (SB 5//.5.1). If you undergo tapasya . . . therefore we prescribe this tapasya: no illicit sex. Our tendency is to have illicit sex. That is the condition of this material nature. But we have to deny it. That is tapasya. Tendency's there. Tapasya means I have got some tendency, but voluntarily I have to check it. That is called control, tapasya. My tongue is dictating, "Oh, let us go to some place and eat such-and-such thing." But if you can control the tongue, "No," that is tapasya. "No, you cannot eat this. You cannot be allowed to eat anything except Kṛṣṇa prasādam." That is tapasya.