I'm all over it! - com certeza!

I can't tell if he's mocking me

 Não sei se ele está me zoando - tenho dúvida seeleestá me zoando

elephant in the room

My dog's finding some good place to "lay one down" phrasal

 My dog's finding some good place to "lay one down"

wind up - "wáind up" phrasal

 to find yourself in an unexpected and usually unpleasant situation, especially as a result of what you do: If he keeps doing stuff like that he's going to wind up in prison!