After adding a slave to Master - Master configuration, slave syncs from only one master Futher to my previous question,

Here is what we have

      +&lt;------+
      |       ^
      V       |
S1&lt;---M1      M2
      |       ^
      V       |
      +-------+


what happens is Upon making any drop, create, update or insert on M1, the slave S1 Syncs the changes in M1. But when we are trying to do the same in M2, we are not getting any changes synced to the slave S1. Any suggestions on how to do that?
You need to ensure you have log_slave_updates enabled on M1, so that any changes that M1 makes via replication from M2 gets written to M1's master log (and thus replicated to S1).

Don't worry, the entries in M1's binary log will not get re-replicated to M2. M2 will ignore any updates which originated from its server-id.