I am answering this as an anwer, rather than a comment, because it is important.
Earth in his comment to my earlier answer to this question, wanted to know .... what are the complications of blowing into a vagina?
When air is blown or forced directly into a vagina, without allowing any air to escape, it could form - an air embolism (the abnormal presence of air in the cardiovascular system). This can be fatal. Women who are more at risk are those whose pelvic vessels are enlarged (meaning, increased blood supply to the vagina) due to a condition such as trauma and possibly pregnancy.
So, if a very large amount of air were to be blown or forced into their vaginal canals, it's possible that the air could enter their bloodstream, causing a blockage in a blood vessel.
As a result, some of these women, perhaps including the pregnant women's fetus, may experience complications. In extraordinary cases, some of these women (and the fetus) may die if the embolism travels to the heart or lungs.