She sounds very shy. Either that, or she thinks you were mocking her or maybe being too juvenile about normal bodily things. I guess you have to convince her that you would laugh if anyone passed air from the back, it was not personal to her and about sex, and you had better never do it again if you ever want sex again.
It's worth being warned that there are some sexual positions that cause the vagina itself to suck air, and it makes an embarrassing sound when the air comes back out. I would avoid those if the sound makes her feel ashamed, and if you cannot control your laughter.
You can convince your wife that this situation is normal. Even in yoga classes, few sounds are heard. One has to control one''s reaction. The above explanation is good enough to convince your wife. During sex play odd things should be taken very lightly.The partner should be convinced that she will not be ridiculed if odd things happen.
thanks for your advise , its mostly happen to ladies than men. i explain to her and further request to come for sex after the wash room
Honey, if you advise your wife that she should only come for sex after she has relieved herself, you had better say it really supportively (such as, "Darling I love you no matter what and don't care at all if someone passes gas during sex, but if you think you will find it embarrassing to have a natural body function like that during sex, you might prefer to go to the loo before we have sex"). If you just say more plainly "Please go to the toilet before we have sex," she will feel even more humiliated than she does already, because it would sound like you find her natural (and accidental) body functions disgusting.