Dick and parabola comparison with Mandy Moon

Brunette cutie Mandy Moon has some problems with math, so she takes additional lessons to catch up with the studying program. Though she honestly tries to focus on a parabola, she still sees dicks everywhere. Her teacher wants her to be a more diligent student but uses the chance to have some fun during the lesson. So, he takes the dick out of his pants and tells her to compare the parabola and the real dick in front of her eyes.