Is "take on" a phrasal verb here? What's it mean?

Native speaker’s answer
Rebecca
No, here, "take on" is not a phrasal verb! Here, the phrase "take your ass" means "go," or "move your body to." With the addition of "on," "take your ass on down" means "go over to the direction of." The "on" is also optional, but it adds a bit of emphasis and is commonly said. Ex: Let's go on down to the fair tonight. I heard it's quite fun! = Let's go down to the fair tonight. I heard it's quite fun! Ex: I'm taking my ass on down to the gym so I can finally do some exercise.