How about this for a more productive bench press/chest day warm up....
Step 1: the kettlebell shoulder mobilisation.
Great for resetting the shoulder into an optimal position for pressing before you train chest. For more info check out my full post on the drill here (the before/after pics have to be seen to be believed)
Step 2: elbow voodoo band mobilisation.
Great for loosening the elbows, allowing for a full range of motion during presses. Once again for more info check out the whole post on this drill here
Step 3: a couple of light sets of your first exercise, ramping up to your first working set weight.
Step 4: have a good workout!