If you're using a kisser button, I can see why you'd be having problems. Back when I used a kisser, it was kinda tough at times feeling for it.

Try what I do now. I tye serving on the string and place the center of my nose on it. The tip of your nose is pretty sensitive and you'll pick up your anchor quick this way. I always have my nose sticking out of my face mask and really took a liking to this setup.