I understand your problem as I do this a lot. Here's what I do lately and it seems to work. I take the inner tube out of the racking tool, or any piece of tubing, put it into the gallon jug. I put the other end in the container I want to rack to. Then I wrap my hand around the opening, so that the thumb and forefinger surround the tube and seal the opening. I leave a small space and put my mouth down onto it and blow, at the same time squeezing to close off the opening as best you can, except for where you are blowing. This starts the siphoning. Takes a little practice, but works every time, and avoids putting your mouth on the other end of the tube to start the flow, which is unsanitary.
Cheers
Cheers