According to Wiktionary "taratibu" would be an adverb:
(It would also be "gently")
From Wiktionary: https://en.wiktionary.org/wiki/taratibu
I believe "taratibu" and "pole" can often be interchanged, where "taratibu" has more the meaning of orderly or composed and "pole" the meaning of calm or careful.
Isn't "pole" an expression of sympathy whereas "polepole" means slowly/gently?
Thanks. That is helpful. I would have used upole normally but I can see how the sense can be extended.