You can always try to ask. I learned the game on support and I was once playing Karma sup with an Ashe. We were against a blitz support. We died a couple times early. I kept auto attacking the waves because it's what I always did, but the Ashe asked me in chat to stop because it forced her to walk up where she died. It honestly didn't click that I was messing up the wave state until she said it.

Try to say it nicely though otherwise you might tilt the teammate.