What is the best exercise to target the multifdi with someone with a herniated disc that is without symptoms?

Chris, I understand both your points, neither answered my questions:
I know the only way to confirm a herniated disc is an MRI, if someone has no symptoms why would he or she have an MRI? So how would you know the disc was herniated? (Unless of course it was for an unrelated or very old problem).
My second question (and I am an RN, as well as a long time trainer with several certifications so I know where the multifidi are) is: How do you train someone to contract the multifidi when they have no body awareness, and cannot even contract the biceps at will? I was looking for teaching tips for such a client, not where the muscle group is.
(and I have taken many courses in human movement science over the years, but am always interested in learning more, so will check yours out, thanks)