Types of pens they use

Art by Skykdotidot, Source (Bluesky)

For those that did not get it: https://www.sharktruth.com/why-do-sharks-have-two-penises/

Yeah, get a flex nib on of of these puppies and platinum carbon black ink and you will never look back at other pens.

https://fprevolutionusa.com/collections/fpr-fountain-pen-collection