I suppose there might be some people who simply aren't affected by it. It's chemical make-up is something we all produce a form of naturally so it's quite possible that your friend has a tolerance to it. It's also really harsh to smoke and if you cough any up on the first hit the little you do take in can produce a short-term tolerance meaning you'll have to wait a while before trying again. I've also heard that using it soon after taking LSD can reduce its impact, but even then it's just a reduction - like a lack of visuals but still getting the physical affects. Other than that I just don't know.
If it had worked properly he would have (according to a survey I found online regarding a cross-section of users) experienced some or all of the following:
- Sense of transcending time or space
- Experience presence of strange plants or plantlike forms
- Have a sensation of the universe as a formless vibration
- Experience visuals of strange machines
- Hear alien music and/or languages, understandable or not
- Experience the presence of intelligent entities in a variety of forms
As I said, not good for jogging ... or anything else that involves your arms or legs for that matter.