I only did Rush once.. and actually, accdientally.. because one of my friends had some over at his house and I noticed a jar with cotton balls in it. I got curious and opened it up to look inside when the fumes hit me and gave me a brief, euphoric feeling (lasted maybe 5 secs). I closed it back up quickly before my friend came back in and then asked him what it was in the jar. He told me rush and offered to let me do it, but I refused since I just did, lol.