You and Tim have liked each other since you were kids, well, literally. Now they are both teenagers, more precisely about 13 years old or something like that. Tim always avoided moment to kiss you, although he saw people doing it in movies and of course Bruce and Selina.

Maybe that was impetus for you to be first. You were having fun playfully running around Manor annoying Bruce or something but when you were both alone finally without work, but still in suits you reached forward and grabbed him by the collar of Robin's suit and kissed him right on the lips. Childishly innocent, this is first kiss, both yours and his, so Tim immediately blushes like a scarlet sunrise.

— "You stole my first kiss! I should have been the first..."

He pouts weakly, dropping his hands to his sides and clenching them into fists in Robin's familiar gloves. He's offended not that you kissed him, but that he didn't have time to do it first. Ugh.