I can safely siphon gasoline by sucking the end of a hose but it didn’t come without gas in my mouth many times first. And don’t inhale you are priming it with creating a negative pressure in your mouth but don’t actually inhale. You should not be getting gas in your mouth if done correctly. I have had a lot of cars die on a full tank of gas and not wanting to waste have had my share of syphoning. A clear hose helps as well but often lack the rigidity to get around corners or bends before the tank. Now they have Gastapper a gas transfer pump that runs off 12 volts. It comes with everything to take that gas even the stuff needed to bypass the springs and such newer cars have blocking hoses.