Warlock Scourge, Vampiric drain can't be used

[Demonic Spirit]

As a scourge warlock , how to use Vampiric Drain ? Hex Storm is not swapping back to it while using Quell. However, while using distortion, using Quell will replace Wingstorm with Spatial Warp.

[MDGeist]

enemy must be knocked down/stunned for vampiric to trigger/work...