[header] How to remove coffee stains from a car seat [title] Pull over if you're driving to treat spills safely. [step] Make sure you are pulled over to a safe side of the road, a parking lot, or your final destination before treating a spill that has occurred. Never try to deal with a stain while driving. 
[substeps] Note that while it's easiest to treat stains as soon as possible, by no means do you need to risk safety to address the spill while driving. It can wait till you reach your destination.