In Twitter there is no option to send more then one Direct message (DM), By default , twitter has allow to send one message at a time. This means time wastage. But it is possible now with a Twitter tool called MultiDM. With this tool you can send direct messages (DM) to 12 different users at a time.
It’s very simple to use. Just enter the TweetGuru MultiDM twitter app page and login with your Twitter account. Then you can send DM (or private tweets) multiple users.