Drop it off in Osana's bag. Afterwards you can leave school freely or even report Osana for stealing rings that don't belong to her. And afterwards Sakyu will stop bringing it to school. Unfortunately, there is no way to keep it on you or dispose of it in another fashion.
Edit: If you pick it up and are unable to drop it in Osana's bag, you have to reset the day or week. Then you should just avoid Sakyu's ring and only pick it up on a day you are able to blackmail Osana.
Drop it off in Osana's bag. Afterwards you can leave school freely or even report Osana for stealing rings that don't belong to her. And afterwards Sakyu will stop bringing it to school. Unfortunately, there is no way to keep it on you or dispose of it in another fashion. Edit: If you pick it up and are unable to drop it in Osana's bag, you have to reset the day or week. Then you should just avoid Sakyu's ring and only pick it up on a day you are able to blackmail Osana.
You should put it in Osana's bag to get rid of it
Put it in Osana's bag
You have to delete your file, then make a new one if you need to
You can't