A quiet office, perhaps with a buzzing fluorescent light or the faint drone of a school hallway in the distance.
Muted, flow-y sounds compared to the sharper pencil, often characterized as a continuous, rhythmic shhhhh . writing_sound_effect_teachers_office_notes_lyri...
Rhythmic, percussive click-clack of an office keyboard. A quiet office, perhaps with a buzzing fluorescent
Intense, high-pitched screech or crackle (if the teacher is passionate). A quiet office
The rhythmic tap-dance of a fountain pen on a student's essay.