How would you phrase this?

Hi, I am a student. My teacher recently changed our seats in our Spanish class. You have to sit at the exact table and seat shown on the chart. The thing is, the person behind me (who sits at another table) gives off an offensive odor (BO). I want to ask to move but I don't know if it's a valid reason to move or not? I feel bad for saying the other student smells bad because they are special and I don't know if they are able to control that smell/take care of themselves properly. And if it is a valid reason, how should I phrase it so a teacher doesn't take it as me insulting that student? Thank yall, love yall teachers!!!