a photo which makes us to feel like sexual attraction quietly and softly, not obvious and directly.
a porn photo there is a girl who is covered to her part of important thing such a pussy but it’s more attractive than perfectly putting off her clothes.
Definition by other languages
성기, 가슴등 중요한 부분을 살짝 가려서, 오히려 성적인 흥분을 높이는 사진.
은꼴사는 은근히 꼴리는 사진의 준말이다.