Oral Sex Advice

My other half enjoys oral and I don’t mind performing it .... We just have one problem 🙃. His Pre Cum tastes really bad causing me to not want to finish ,but I do resulting in him finishing and me having that nasty taste in my mouth again. We are usually very blunt about problems we have, but I don’t know why I can’t come to tell him this... any advice on the best way to tell him ?