For "we're throwing down", it can be understand as "we're throwing down (the gauntlet)". This does not mean to meet a challenge but actually to issue the challenge! :)

"Your sorry ass" = a crass way of saying "you". "We’re throwing down" = I understand this as a physical fistfight, but I often see it used figuratively to mean "meet a challenge". I see it often used in North America, but not really anywhere else, so I'm keen for a clearer explanation if there is one.