I ain't on that shit! - You're saying you're not going to put up with whatever nonse

You're saying you're not going to put up with whatever nonsense someone is doing.

I ain't on that shit! You're acting like a toddler and I ain't going to tolerate it.

I ain't on that shit! You're arguing with your mom and I'm not going to get in the middle of that.

I ain't on that shit! You're getting in trouble and I ain't getting in trouble with you.