If you go to wowhead and view in 3d any model that is available to players, you will see that among animations there are three called LocSpellCastBothFront, LockPrecastBoth and LockPrecastBoth.
I've never seen them on spell effect previews video, and these look very warlocky. This seem to be new animations like what mages/druids/priests/shamans got in 7.3.5.
Like, this might be new Channel animation for Hellfire or Rain of Fire: