Affection is like honey. It sticks to everything. It has a quality to get attached. When the mother is embracing the child in her lap, she looses her sense of self and becomes one with the affection for the child. It is so strong that both the child and the mother loose themselves in the moment. The mother knows the child is her own. She posses the child and wants the child to enter her heart . The feeling is to simply stuff the child inside.
Affection has this at the base. It wants to posses. It wants to own. It wants to pull the object of affection inside the area if control. It wants the honey thread to become the rope to pull inwards, to simply own. All the energy is inwards directed.
Compassion is also the same energy, but it is like light. It radiates. It moves out. It wants to illuminate. It wants to melt the suffering by warmth of love. It feels joy in giving love. It seeks nothing in return. It flows out from the white part of the eyes. The black part gets the visible light in. The white part transmits compassion towards objects on focus.
Affection is the start point with a pulling inwards force. Compassion is a radiating force which develops gradually.