So I’m guessing he wants a custom case made by himself, here is some info I can Provide.
A case (I used a Metal Lunch box before, worked great)
Foam (Measure how thick the case is then get the appropriate foam thickness)
Tomate Paste Can, the one that is small in diameter
Step One: Measure Width and length of case
Step 2: Place foam inside the case
Step 3: Decide how many holes you want and where they should go
Step 4: Use tomato paste can to cut the holes by twisting. Dont twist back and forth, only twist clockwise to prevent jagged edges.
Step 5: Put your yoyos in that case!
Hope that was helpful enough.
If that wasnt helpful enough for you, heres a video: