what's the best way to ask how to use the bathroom?

so as the title presents i'm just very confused on what exactly is the best way on how to ask to use the bathroom. i'm a high school student taking french as an elective and my french teacher has taught me to say "je peux aller aux toilettes" but i've also seen some people say "puis-je aller aux toilettes" is the better way to ask but that those two only really work in school settings.. and that "ou sont les toilettes" is the best way to ask in just casual conversing (outside of a school setting). so what exactly is the correct form for asking???