SweetPeas are smileys that are only available to CafeMom members.
To add a SweetPea, go to any place where you can enter text (a journal post, group post, comment, etc.).
Right above the box, you will see a button labeled "Add a SweetPea". Just press that and you'll get a pop-up window where you can select any of the SweetPeas you want to add to your post.