We all do what we can to help students understand especially when you are surrounded by students who know little about the basics of English. Our basic style is through facial expressions and gestures. But we can use real items and situations to help students to understand. If you are teaching animals you cannot bring them to school but you can bring mini toys to help make words stick in student's heads with school permission. However, don't use student's characteristics as an example to get the information into student's heads. As an example, if the card is big, don't call the biggest student to the front of the class and say, “He/She is big” or the tallest student or the shortest student.
The first reason: Most students are sensitive at a young age and may not like who they are, yet.
The second reason: Memorized expressions with characteristics of students, may cause the students to call their classmates that name in school in English. “Hey, big!” “Hey, short!” “Hey, tall!”
You don't want your English lesson words to be the cause of bullying.
If you need help with explaining, work with the Japanese school teacher to find the best way to get the point across. 😎