Chastity refers to Mr. Knight as a boy who tries to prove to a young attractive person that he is a true man, not just a boy, by demonstrating his ability to relate to male students.
Amia Miley dislikes being attentive in class and over-studying, and her professor is sick of seeing her act sloppy. To improve her GPA, he wants Amia to put in a lot of effort in certain unapproved extracurricular activities.