It is important to note that ‘each other’ is always used as a singular pronoun. This means that it should always be followed by a singular verb, even when referring to multiple entities.

However, you should point out to students that each other is treated as a singular pronoun and emphasizes two or more separate people. Each other’s is always correct, and each others’ is never correct. Think of it this way: You would say We talked to each other for hours. You would never say We talked to each others for hours.