Don't know how to communicate a "fetish"

So long story short im in a really healthy and happy relationship,it's been almost 3 years. Yesterday we were out for drinks and after coming home drunk she didn't feel so good and had to vomit. She couldn't do it tho and after trying and failing for 20 minutes she asked me to put my fingers down her throat to trigger her gag reflex since she couldn't do it. I did and that turned me on REALLY bad but I don't know how to tell her, she is absolutely disgusted by puke and hates it but that sent shivers down my spine I liked it so much. what to do?? lol