This activity is designed for 中学 2年生 to practice the auxiliary verb "should," but also incorporates "must" since they're taught in the same unit in my textbook. The basic structure of this activity is very simple, so you can modify it just about any way you like. I've written it here in group relay format, but it could easily be adapted to pair or solo work!
PREP
print, cut out, laminate situation cards
print worksheet, one per group
lay situation cards face down on a desk at the front of the classroom
ACTIVITY
Divide student into groups of 4-5. Pass out the worksheet and have students determine their own relay order (Student A, B, C, etc).
Student A goes to the front of the room and chooses a card. Each card has a simple situation, for example "at the movies," "on a snowy day," "when you're studying." Student A brings this card back to their group and writes it down under "Situation #1" on the worksheet.
The group works together to think of three sentences pertaining to this situation: one thing they SHOULD do, one thing they SHOULDN'T do, and one thing the MUST do or MUST NOT do (the team can choose). For example, "at the movies"-> You should eat popcorn. You shouldn't talk on the phone. You must buy a ticket.
When finished with Situation #1, the group brings their sheet to the ALT or JTE for correction. Once they have the OK from a teacher, Student B can get a new situation card. Repeat steps 2 and 3.
You can set a certain number of situations as the goal and turn the activity into a race, or simply have students complete as many situations as possible in the given time.
NOTES
Before beginning play, I chose a few situations to brainstorm with the whole class as a warmup.
I've attached the situation cards and the worksheet I made, please alter them as you see fit! The worksheet is meant to be double sided as I could only fit four questions on one page lol