Detective Conan, what episode happened in the swimming pool?

Yingyou and Xiaolan went to the bathroom because Yingyou slipped in the swimming pool and her clothes got dirty. When Conan heard about it, he thought they were taking a bath together, and he was anxious to think: that guy! Why didn't I take preventive measures? ! After entering the bathroom, I saw Yingyou naked and Lan was helping him get dressed, so I asked with malicious intent: What are you doing? ! After listening to their explanation, I was still very unhappy until I found out ...