It's their annual health check, but the doctor's diagnosis is a little strange! He checks their anuses relentlessly, inserts his fingers to massage their anus, inserts anal beads while they're on all fours, and tortures their anus with a vibrator on the delivery table... The girls in uniform know it's strange, but for some reason they can't resist! "Sensei... something's wrong with my body..." The JKs moan as they have their anuses explored for the first time, and gradually become addicted to it!