Even with the paranoia (and necessity, honestly) inherent in the question, Tonks couldn't help but smile. "On the train! I popped into your car on the train, turned my hair Weasley red, said, 'Wotcher, I'm Nymphadora Tonks, but just call me Tonks because Nymphadora is a poncy name and my mother was clearly mad when she gave it to me', then plopped down beside you and promptly tried to filch your chocolate frog."