That a great idea but for me this technique is a little unpleasant to do.

But one thing you can do to pinch your nose without looking like a nutter is to put both your hands over your mouth up to the nose and block it with the tips of the fingers. The posture of the hands is with the palms pressed together ( like when you are praying ) but you put them over your mouth and nose. This is a more normal gesture than pinching your nose with one hand.
I hope you get the picture, if not I can draw one...