Soap that makes your privates smell like fish?

I know I've read it before in one of those "women" magazines, but does anyone know which ingredient it is that makes your privates stink like fish?? I know it's in soaps like Zest, Coast,etc...yes they smell good but make a guys or girls vjay stink!! I'm not imagining this because I've been told this by other people, and like I said, I read it in a magazine. I just can't remember the ingredient. My sister called me crazy, then told me she witnessed it with her husband..lmao!