We would suggest to you to do a little research on female anatomy, because the vaginal wall is nowhere near the ovum, but futher inside past the cervix,to either side of the womb. If you do not use an extremely long tounge, which is quite difficult, you may cause infection to her. Considering the condition of the human mouth, I would suggest it is better to limit your love play to the area of the clitoris, which the the most sensitive part.