BJ help

A.S.

Looking for advice and tips on how to give a BJ without gagging or vomiting? I can go longer and more comfortably if I tilt it a bit towards my cheek but my husband likes it to be straight and more toward my throat. When he moves my face closer I start gagging and once even threw up a little. I actually enjoy going down on him and even crave it at times but just dont know how to get past the gagging stage

Any advice or tips? Please help!