No particular routine, just a lot of different things. All of which get met with grumbles
Not sure I can explain many in text alone, perhaps I'll get the camera out and shoot some pictures, but here is a few things to try:
Lie down on your back, ball above your head, arms straight. Keep your arms straight above your head and stand up. Lie back down keeping them up there. Repeat.
Situps - Have someone pass you the ball, go down, throw it back to them on the way up.
Play catch. Straight from the chest push off, pass back and forth.
Make a circle, facing in or out. Don't move your feet, pass the ball around. Add enough balls to keep the pace quick
One person in the middle, facing forward, one on each side. Have the side people pass the ball in, middle person twists to catch, twists all the way to the other side, and then back throwing it back to the same person. Don't move your arms, throw entirely from the twist and the legs simulating a hook. Other person throws the ball in as soon as the first one is thrown out.
One hand on the ball, pushups, jump back and forth between which hand is on the ball.
Both hands on the ball pushups.
Lots of fun things, be creative, but make sure it's not something that will do harm