I didn't quit caffeine, but I cut down massively by keeping it in a Zojirushi mug that keeps it hot all morning instead of drinking from a regular mug. Because it stays hot, I just sip it, and that way I only drink one mug in the morning and occasionally one in the afternoon, instead of the 3 or 4 mugs I would drink previously.
Similarly, I use a really skinny mug that keeps coffee hot longer than usual, and I make sure it stays hot by going back to the microwave and reheating it as needed. The heat keeps me from chugging it. I also brew half-caf and mix it with half water before heating it. I know I sound like a crazy person.
Edit: Nevermind, its the cooling surface of the top of the coffee directly exposed to air. I'm just over here thinking about spherical chickens in a vacuum...