Experience, maturity, don't play mind games, she knows exactly how her body works and what she wants, and she has her own home. It's a lot easier to have a fling when she says "come over to my place tonight" instead of me dealing with an apartment full of college roommates. I've had about 25 partners in my life, and only one was ever younger. It's a real turn off when you're 20, she's 18, and right after we finish she says "oh crap, my parents are home!" With all the 30-40 year old women I was with I just stayed the night (which also meant going at it over and over). I even had repeat encounters with a woman in her 40s in her office because it was HER office. She was the boss. When the home or office weren't available, we got a hotel, and it was a nice hotel.