Or, according to Dune author Frank Herbert, from watching a man climb a mountain. (See Heretics of Dune)
To be fair, not a single character in the Dune universe is a regular human. They’re the equivalent of those plum-sized GMO strawberries at the grocery store.
Yes, I choose to believe she was rubbing one out with her prehensile clitoral hood.
There are no GMO strawberries for sale. There are none currently approved.
Well, they all are, just through the old-school methods of domestication and selective breeding.