I shouldn’t have shown this to my teacher

I attend to an evening Finnish language class. Last week during the break I went to the WC and saw this poster. I knew the meanings of first two words but didn’t know what “Runkulle” means. So, I took this picture and used Google lens to translate it. Google translated it as “For the trunk” which doesn’t make any sense. Then I went back to the class and told the teacher that there was a poster in the toilet asking why did you come to the toilet. She laughed and asked me what was in it and I told her I didn’t fully understand it and looked at my phone. Then she asked if I took a picture. I said yes and showed this to her. Her face instantly changed and she looked appalled. I knew something was wrong. Then she brushed it off like nothing happened and continued the class. When I went home I asked the meaning of that word from ChatGPT. Instant regret 😭. Now I am embarrassed.