Female vaginal discharge. First, consciously there is a gas in the vagina that can't be discharged involuntarily; In another case, during sexual life, with the twitching of the penis, there is a sound in the vagina, as if air is discharged from it.

This is because vaginitis patients, because bacteria ferment in the vagina, produce a lot of gas, so that the air pressure is greater than the external pressure, leading to vaginal blowing. So you need to go to the hospital to check the cause and treat it later. For reference.