I DO IT ALL THE TIME!!! its fairly easy, my friends.
1) Find an item that makes a good catch game! (soccerball/football/frisbee.etc.)
2)Use L1 to aim at the person you wish to play with. (girls usually run away)
3)while holding L1, press and hold R1
4) in most cases they will make a signal, mostly a slight gesture, or a 'throw it here' gesture, youll know.
5) let go of R1, and they will catch (make sure theyr facing you!!) if caught, they will usually throw it back, as long as the L1 button is kept, or you dont move.
6)Once they throw it back, press triangle at the right time to catch.
7) Repeat
(the catching took me a while to figure out. lol.)