That’s nice of you! I’m sure they’ll appreciate it. Few things are worse than letting someone borrow your car, then receiving it a few days later full of receipts and loose French fries with less than a quarter of a tank of gas.
You can open the 2012 Honda Civic’s gas tank by pulling the little lever with a gas icon. It will be near the lever you pull to open the hood. In some models, it’s just to the left of where your left foot sits as your drive. In others, it’s on the floor to the left of your seat. Then, you can just pop open the gas tank cover and unscrew the cap to pump your gas.
This is unlike newer Civic models that did away with gas levers and gas caps. In these vehicles, the gas cover is spring-loaded so that you can press to open it and push the gas hose directly into the tank. No need to unscrew or keep track of a cap!