Product specific extra checkout fields?

I need some extra fields to show during checkout when only using specific products or even just virtual products. I can’t seem to find where I can toggle the extra fields to show only on certain product but I did notice this in the features list “Show or Hide added field for Specific Product or Category Only.”. But I’ve looked everywhere. My added fields show on every product which doesnt make much sense. Hoping you can point me in the right direction.