I agree with @buzz13, depends upon how many dates in we are. I'm generally not comfortable farting in the beginning but you better believe when I'm comfortable with you I'm letting them go. I'm especially gassy in the morning.

As Shrek says "Better out than in."

If we are walking our dogs I say, "Leo shame on you". Leo's my dog. If no dog around and it's a 1st, 2nd or 3rd dateI just ignore it. If we made it to the 4th date (amazing she went out with me again) I might say something witty but never ever use it against her.

This may come as a surprise to some people but, yes, women fart too. The correct response, therefore, is to laugh and say "Oh, must have been the borsht [or whatever the most fartifying component of the dinner was]" before returning to your conversation, just as you would if a man farted.