Laugh Out Loud - Mein Baum

So I’m in my ballet class and struggling a bit with maintaining the right posture. My instructor pats my tummy and says to keep trying but to be careful. I laughingly try to say that I can’t use my stomach muscles so well...unfortunately, this is what came out of my mouth: “Ich kann nicht so gut machen mit mein baum”. She chuckled a little, which seems to be normal for me. Now I know that sentence wasn’t grammatically correct, but it’s hard to dance and speak in another language. I move along laughing at my poor German, when it hits me. “Baum” isn’t the word for stomach, “Bauch” is!!! So basically, what I said to her was: I can not use my tree so well.