Simply visit the users profile page that you wish to gift to. In the top right hand corner of the page, you will see a gift icon similar to the one below. Tap the gift icon to be presented with a list of special emotion categories that are available to be gifted to this user and tap the category that you wish to gift.
You can chose to include your username with your gift or send it anonymously. You can also send a short personal message with the gift that the recipient of the gift will receive when the gift arrives.