Yeah it happened all the time for me. Funny thing is, I could control it far more than she could. Once hes in and the air has made its way out there is a vacuum that occurs. He needs to learn to avoid pulling out, or going almost all the way out and letting air get back in. Theres no way hes never experienced this before if hes sexually experienced or doesnt have tiny peter.
Also, rather then letting a little bit of air come out, have him thrust in fully and get it alllll out in one big wave...yes it will make it louder, but it will not happen again until HE lets air enter the vagina. Hes gotta work at it so he can pleasure you the way you want. This is just my experience, i dont know everything.