actual gasoline? I did it once by accident, was sitting outside reading a book about this time of year (summer in northern hemisphere), and didnt notice the fumes coming off a nearby gascan, until I did, and took a few breaths. I blacked out, came to, hallucinated for a few minutes, then spent the next several hours violently ill. I like psychedelics and getting high, but I have never repeated the events of that day. With gas, you risk serious fire hazard and if an enclosed space, asphyxia, which means outdoors only, which leads to problem #2: if anyone finds you fked up or passed out, you can pretty much guarantee that parents, cops, paramedics,etc are gonna get involved. I wouldnt recommend doing it to anyone, not because I read in some book that it's bad for you, but because the trip is short, the comedown awful, and the risks are not anywhere near the 'reward'.
There's also the fact that you will find very few 2nd+ trip reports because ppl who foolishly try it usually say 'fk that' and never try it again.