SmeagleGoneWild's post in Hold Laser? was marked as the answer
Yeah im almost positive you have to hold it the entire time. However, what i may suggest is a LOAL (Lock-on After Launch) where you launch the hellfire and then lase about 10 seconds (itll tell you when to fire the laser) and thatll guide the hellfire down onto target. The ACQ source needs to be a target point so that the missile knows where to go essentially versus in direct, you just fire it at what youre looking at. Watch wags video or casmos and they have a better visual representation of it.