By default, only people you follow can send you direct messages on Twitter . If you send to non follower you will land in request tab and it does not push notification (I tested from many types of accounts).
So let us say you want to DM account A and you have a set of accounts B C D from where you want to send the DM. You need to make A follow one of the accounts B C D before being able to send message to account A from one of those (without landing in request tab and pushing notification). Making someone follow an account is not something that can be done in a deterministic manner .
In those conditions, I would call it more Mother/Slave (follow and when follow back DM) for Twitter rather than just Mass DM…