Proper breathing techniques allow more air into the lungs and improves its efficiency. (whydetox.net)
My guess would be that she isn't getting on the breast deep enough and therefore is getting more air in while she eats. (justbreastfeeding.com)
If you're under hard acceleration, it could open the intake valves slightly ahead of time to allow more air into the combustion chamber for the ignition stroke. (cambridgecentrehonda.com)