Metahuman - How to Animate Lips Part (AU25)?

I specifically need to animate the lips part action unit on a metahuman, however, I found no direct control for this movement. A combination of which controls do you think would best mimmic this motion? I tried jaw drop but this is too dramatic even with slight activation.

I am using this as reference: Facial Action Coding System (FACS) - A Visual Guidebook - iMotions

Thanks!