You can log into each product in the Teachme series from the following URL.
https://teachme.jp/select-product
- Each product also has its own individual login URL.
Additionally, if you are logged into any one of the Teachme series products, your login status will carry over to the other products as well.
Whether you can Log Out depends on the product.
You cannot Log Out from the Settings Center.
Reference: Log into the Teachme series product selection screen
https://teachme.jp/8/manuals/51248656