If there is gas coming out of the bottom of the 18-year-old, similar to the sound of a fart, it is clinically known as a blowout. If there is no history of childbirth, it is often due to the fact that the fat in the pelvic floor is relatively low due to the relatively thin body mass, so the front and back walls of the vagina do not fit together, and the air easily enters the vagina and is then excluded with movement, making a sound similar to a fart. In this case, it is best to improve your health, strengthen your nutrition, increase your weight and pelvic floor fat, so that the front and back walls of the vagina will no longer fit together. It is also recommended to do anal lifting exercises twice a day, 30 strokes each time, so that you can exercise your body muscles and reduce the occurrence of this condition.