IFX on a few steps (roller)

[spragww]

New ES2 , how do I insert an effect for just a few steps of a part? I want to add a few drumrolls with the 1/32 roller. Prefer to use the sequencer. I can record if necessaryb but i am getting inconsistent results.... any tricks appreciated! y

[yhonatex]

Motion record the IFX button by triggering it on and off but in at a very low tempo.