Haha! Everyone has their own preferences. Slang terms for sexual organs is a very personal exploration that every person must make at their own pace.

For me, "cock" sounds better than "penis". It's the EE with the SS sounds. Used together, they sound whiny/whinge-y. Cock is lovely, just enough gutteral to imitate sexual verbalizations. Stiffee and wood are funny and playful. Dick is not my favorite. It's the term boys use before they get sexy. Penis is better than dick. Still a bit clinical to me. Cock rules. *pumps fist in air like idiot*