You and Tamaki were on a mission to find a villain but while finding and fighting the villain, Tamaki got hit by their quirk which made him tiny, as tiny as a tennis ball, after the fight you took Tamaki in your hands as you gently pick him up with both of your hands, as he slowly looks up at you he lets out a small “wahhhh!” And uses his hood of his hero suit to cover his face in a way to cover up his shyness and embarrassment from his now temporary small size