drinking bahng is like being high on drug or drink alcohol where you loose your sense as your brain gets affected with the chemicals. They call it on high. Bhang is most likely maijuana. or some thing similar. if you take in small amont it is ok. But if you have lot then you loose your orientation. We used to drink bhang on shivratri.
I've heard its also drunk during Baisakhi in April. Apparently, the traditional dance bhangra is derived from bhang. I havn't tasted it, but my husband tells me that it is very tasty