The controversial demonstration took place February 21 after Professor John Michael Bailey's course on human sexuality.
Some students and faculty say Bailey is known for sometimes pushing the envelope.
What happened at Northwestern is so disturbing to Robyn Mathy, an independent researcher based in Oregon, that she plans to file a formal complaint with the American Psychological Association.
"We have a responsibility as instructors and as professionals not to engage in behavior that is going to be shocking, alarming, confusing, disturbing to our students," she told ABC7.
Mathy has taught at multiple universities and published dozens of peer-reviewed articles on human sexuality and ethics.
Bailey, who presided over the controversial sex toy demonstration, is not accredited with the APA but Northwestern's psychology department is.
"They will do their own investigation and the sanctions can go all the way through having the department lose its accreditation," said Mathy.
The 100 or so students who witnessed the demonstration were first given multiple chances to leave.
Senior Justin Smith who was in the audience says students were told the material would be graphic but not how graphic.
"Disbelief. I didn't really know how to react and as I looked around, I really don't think anyone else knew how to react. Girls were covering their eyes going, 'oh my gosh,' not necessarily in a bad way, but you can't believe it was happening," said Smith.
Smith says he felt no pressure to stay, but Mathy questions whether some could have misread the context of the warnings.
"If I say to a student this is going to be completely voluntary but it's in a classroom, then I have to appreciate the fact that because I have more power than the student, the student may nonetheless feel that it is really optional," said Mathy.
This isn't the first time Bailey's work has stirred controversy.
His 2003 book about transgender issues entitled "The Man Who Would Be Queen" was both lauded and assailed for research methods that some considered unethical.
"He has developed the reputation of engaging in prurient behavior under the guise of human sexuality," said Mathy.
"This is one of the best universities in the world, freedom of academic pursuit, that's the whole purpose of professors being tenured and students attending the university. I don't think he should be punished at all," said Smith.
Since Wednesday, Professor Bailey has not responded to multiple requests from ABC7 for comment. Northwestern's president has promised a full investigation into the matter and clarification on classroom policies.