Been making a lot of progress doing these of late...
You can do them without a partner if you have an incline situp board. There are plenty of variations - punch combos like above (alternatively you could position the situp board infront of a heavy bag and swing to kill), hold a couple of DBs for presses, curls, etc. You can even use a BB or a sandbag held to your chest. Try it out. As fun and effective as they are painful.