If you're right handed: bottom right corner in the fold of your palm, supporting the back with your ring and middle fingers, and support the bottom edge with your pinky. Works fine as long as you're not gesticulating aggressively with the same hand.
iphones before the 5 had 3.5 in displays even the 5 has just a 4 in display, so they are even smaller (and thinner and lighter) than a Galaxy Nexus
FYI, all iPhones before the 5 are thicker than a galaxy nexus and their weight was between 2 grams lighter and 5 grams heavier.