took it a few times years ago... used to after getting back from all night out clubbing.. do not mix it with Alcohol, overall it can be fun but it basically cuts off the receptors in your brain so you go into a more vegetative state.
Movement feels funny and its relaxing take too much and generally everything slows down to a crawl... very slow passing of time etc. If you have had an operation it feels like just before you get knocked out (given that its an anesthetic for animals) but obviously you dont get knocked out.
If you are drinking Alcohol and you take it you are going to dry heave and throw up and it wont be pleasant.