It's always great to have a workout partner at the gym. Not only does it provide you a "spotter" but you can push each other to get the most out of your workout!
There are many benefits to Decline Bench Presses:
The first benefit of the decline bench press is that it targets the lower portion of your chest better than the flat bench as well as the incline bench. This is extremely important if you really want your chest to be round, wide, and defined. Adding them into your lifting routine could really help you fix imbalances that you may have noticed in your chest due to lack of lower-pectoral stimulation and could help increase your chest strength greatly.
Another benefit of the decline bench press is that it is a powerful chest move that take your shoulders out of the equation a bit more than its flat or incline counterpart.