Oh, lord, I believe you have been GREATLY misinformed. You should NEVER insert ANY kind of food into your vagina. It does not matter if the food was boiled, refrigerated, pasteurized, etc. It still has bacteria in it. And some of those bacterium have NO business being introduced to your vagina. Opening up a tampon, then opening the yogurt, then inserting the tampon into the yogurt can introduce even MORE bacteria, as airborne bacteria are EVERYWHERE. It does not matter if you wash your hands, it does not matter if you use a spoon to apply the yogurt: anytime you open something, regardless of whether it was sterile or not to begin with, an introduction of bacteria occurs. Sugar is one of the WORST things you can introduce into your vagina, as bacteria, healthy or not, LIVE off of it. An overgrowth of healthy bacteria can cause just as many problems as introducing foreign bacteria.
Please, go to your doctor, who can prescribe you something for your odor, something designed for the female anatomy. If you have any off-odor, you need to be checked out anyway.
Yogurt is meant for EATING, and eating yogurt is not only good for your GI system, it can also normalize healthy bacteria and pH in your vagina. Yogurt can also help prevent yeast infections, but it cannot cure one.

motherofhighspiritedones, I hope you are not thinking that Adam and Eve or even your own grand parents had a drug company in their back yard. Natural cures have been around for ever and even though we may have replaced it with drugs today for our own comfort, it does not make these any less valid. Do not think of yogurt that you put into your vagina as food. Think of it as medicine. Once you put it in your mouth it is food.

For yeast infections, unpasteurized (the cultures are still alive), unsweetened and unflavored yogurt that contains live acidophilus cultures can be used as a topical cure. The acidophilus bacteria is the natural enemy of yeast and it will restore the natural balance of your vagina. It is very important that it is UNSWEETENED. Sugars are the food that yeast loves the most so be warned!!