In hatha yoga, evacuation is important to be sure that the body does not hold waste any longer than necessary which means that the waste is released from the rectum as soon as it arrives there having descended through the colon.

The best posture for evacuation is a squatting position but the modern commode discourages that. It is a great invention, this modern commode. It services hygiene globally but its disadvantage is that it is designed for sitting and not squatting. Sitting to evacuate is easy but it discourages and to a degree impedes the muscular actions which are involved during evacuation.

When one squats one can access the expulsion muscles much more efficiently. If not some waste may linger in the rectum or colon and that makes for a more inefficient clean energy, resulting in the kundalini being on a lower plane of consciousness which negatively impact the meditation and dimension-accessing process.

Can one squat on a modern commode?

If one has a supple body one may do that safely, otherwise it is dangerous because of the possibility of slipping. In some Asian countries modern squat toilets are in popular use.

There are several squat positions. I was inspired to do variations of one which currently I find to be the most effective one to operate the expulsion muscles of the rectum and lower colon. This posture was shown by Yogeshwarananda. See it below. The hands should hold the calves, or thighs or feet while the evacuation pressure is applied. This will cause the expulsion force to go downward. Otherwise if some of it goes upwards, there will be less pressure on the waste with the result that there will be no or just some waste expelled.