You can put bands around the end of the bar, but I like to attach one to the rack so that it's providing resistance at the waist during the movement. It also acts as a cue to "get your hips through."
Keep your knees barely bent during this movement, and use a controlled eccentric and a somewhat powerful concentric for each rep. You need to think about pushing your butt out and into the wall behind you while maintaining this "soft knee" position.
Hold the top portion of the movement for a second before starting the next rep. You shouldn't look like you're dry humping the band. Do 4 sets of 12 reps.