Safety experts caution against the unsafe practice of siphoning petroleum by mouth, warning especially, that it can result in loss of life.
Beckson's answer is the patented "Siphon-Mate™" pump; a combination displacement lift pump and siphon pump with valves suitable for transferring fuel.
Pump to start flow. Fully extending the handle will allow siphoning provided that the source is in higher elevation than the receptacle. Lifts 4 oz. per stroke.