User blog comment:DoctorAsawa/Sebastian, the Drumbeat of Freljord/@comment-8267817-20130509154211/@comment-5514182-20130509220436

Ok, so here's how the passive works: At max rank both Q and W are cast 3 times every 3 seconds. This means +30 Movespeed. The buff doesn't refresh but because Q and W are constantly on, so is the passive.