If harbor seals (Phoca vitulina) can have a "soft mouth" this one has the skill down. She was incredibly gentle, nibbling the fin without engaging her teeth.
Seals often take my fins for chew toys, but this is the first time they've gotten the mlem treatment. I wonder if this polite pinniped learned to avoid painful chomping like a well-socialized puppy, or maybe she was just making sure I was up to her taste standards.