Kim competing agains his monkey at P.E. class
If kwamis were actual size Tikki would be the least obvious as ladybugs are easy to hide, while each day would be an adventure of Adrien trying to sneak a cat into the class, or Plagg (who still has all the normal kwami powers) sitting on the steps of the school, curled up in the sun, waiting for Adrien to come back, maybe sometimes staring at the doors Damocles slammed in his face mewing, other days finding his way onto the roof.
That or Mendeliev or Bustier has a soft spot for cats, brings it inside from the harsh weather conditions (it’s 20 degrees, a few clouds but mostly gentle sun) and Plagg now spends the whole day at the front of the class being pet by teachers and whichever student is doing a presentation.