I want to know, how do we know when we are burning the seeds of karma?
Is it possible that while doing Kriya, negative experiences can occur because of the liberation of the seeds?
And do you recommend doing Kriya, during a psychedelic trip?
It isn’t always clear when we are burning up seeds of past karma — it is more noticeable over time, as people feel spiritually lighter; more joyful; growth in spiritual qualities such as devotion, kindness, and selflessness; and with less attraction to worldly and sense attachments. Spiritual progress doesn’t always go in a straight line, however, so most kriya yogis can continue to have some ups and downs in the short term. But long term, the effects tend to be more apparent.
Sometimes during Kriya practice it will happen that a particular thought or desire might pass through the conscious mind. Swami Kriyananda has likened that experience to having a particular karma dissolved, and then passing momentarily through the conscious mind on its way out. When Kriya is done correctly, with devotion, attunement to the Guru, and a certain amount of depth and calmness (and without doing psychedelic drugs!), it won’t cause negative experiences. This is one reason why it’s important to sit in the silence for at least fifteen minutes after finishing Kriya practice, as Paramhansa Yogananda suggested.
One definitely should not have a Kriya practice at the same time as a practice of doing psychedelic drugs. It could be especially harmful to do drugs at the same precise time as Kriya, but even if not done at the same precise time it could still be harmful.
Here is a much more lengthy answer to the general question of trying to use psychedelic drugs for spiritual growth.