2 are pick up 2 unless you are on 2's. Jokers block pick ups. If a 2 of D is layed, you can lay a K of H, and not pick up a single card, the player to your right has to pick up 9, etc,etc,etc. Suits are not relevant when you are facing a pick up card. If you have to pick up, and you get a pick up card, you can lay it,but only at its original value.
Jokers stop any picking up, or can be added to make a pair.
Only lay a pick up card if you have another one in your hand. It could blow up in your face.