The average penis size is around five to five and a half inches [erect]. It's really about finding the right O-inducing position or move. Still, if your dude seems concerned about slippage—or you've experienced that IRL, here are six positions that are sure to satisfy:. Any position where the woman is on her back and her legs are in the air works well for a smaller penis, Marin says. So, lie back and pull your thighs to your chest while your partner positions himself over you. Drape your legs over his shoulders for entry, positioning them on either side of his neck, or even over one shoulder.