Video from Six Flags Discovery Kingdom in Vallejo shows Siku demonstrating her sit-up routine.
Despite weighing just shy of a ton, or 1,750 pounds, it seems like Siku is pretty limber.
Just last Sunday, Harbaugh had some fun at Six Flags with Siku, who matched the coach push-up for push-up.
The video was posted on YouTube and got national attention, even airing on "Good Morning America."
Proving it was a friendly competition, Siku gave the smiling coach a big smooch after.