go to shop- then on left you'll see a tab for your "inventory." click on that and the screen displays all yoru collectibles for you- there is a "gift" tab next to the giftable collectibles. click that, then in the new screen you enter the name of the recipient and type any message. voila!
(be sure to spell the name right (including any spaces) or it may go to the wrong user and then you have to pay bells and wait a week or more to get it back!!)
You go to the shop then go to your inventory, then you click gift on the collectable you wanna gift. Then type in the user you wanna gift it to through the transfer pop up.