Gigantic. It's not a word you use to describe a penis. It's too bulky. Women want softer words. More exotic words. Words that whisper and moan.

Never start with sex either. You start in the middle of things and the audience has nowhere to go. I recommend a bus stop. You get a conversation going. Maybe about how yellow the daisies are lately or why the bees are dying.

Of course you'll think the audience will get impatient. Get to the hard core sex already! But they won't. Anticipation and all. I once wrote a story that had fourteen pages of the main character (His name was Rod Tippington) talking about his Russian doll collection before getting to the man on man on man scene. I won an award for that one.