"I wish the teacher was 3 feet shorter, but her breasts and ass stayed the same size, and her body was well proportioned." Sure enough, the teacher's body began to shrink in size, but her assets remained their full volume, but now appeared even larger. Yet, she still looked normal, and not like an abnormally short person. With a grin, you stood up and walked over to her, dick fully erect now.
She took notice of you, but did not say anything as you proceeded to strip her. Her breasts bounced upon being released from their cloth prison, and her ass swayed lasciviously. She blushed at feeling you prod and grope her body, making her moist down below. Somehow, she still managed to focus on teaching the class, even though she moaned every now and then.
But you wanted to take this a step further; picking up the significantly shorter and lighter teacher, you drop her right on your dick, penetrating her with an easy, slick thrust. "Aaaah!" She moaned, enjoying the sensations. Up and down, you thrust your hips, finding the teacher hilarious as she still taught the class despite having sex.