I use this spell a lot during Mob fighting. Whenever a healer or caster gets agro, pop this sucker on the mob and the next time someone hits him - tank - he turns around and fogets about that poor healer or caster. Works wonders and it almost always casts and STICKS for me.
Downfall now though... the lullaby spells got nerfed and now have a 10 sec timer. It needs to be dropped to like 5 seconds.