Circle of Affliction

[Angelfyre143]

Can circle of affliction be used more than once for the attacking source?

[Roxas]

Please make sure to post the card's Oracle text when asking rules questions in the future.

Circle of Affliction {1B} |Enchantment| As Circle of Affliction comes into play, choose a color. / Whenever a source of the chosen color deals damage to you, you may pay 1. If you do, target player loses 1 life and you gain 1 life. PLC-U [Vin Leg Ext Std legal.]

No, it cannot be used more than once each time you are damaged. You can use it twice if, say, you chose white when you played it, are attacked by a white creature with double strike, and the damage is dealt both times. Otherwise, it only triggers once every time a source of the chosen color deals damage to you, and so you are only given the option to pay 1 once.

[Playboy514]

If an opponet attacks with multiple creatures, can you use CoA for each creature?  All of the creatures being of the same chosen color, of course.

[Khahan]

If an opponet attacks with multiple creatures, can you use CoA for each creature?  All of the creatures being of the same chosen color, of course.

Yes. Although combat damage goes on the stack and resolves as one object, each attacking creature is a separate source of damage and will trigger circle.