The tangerine sing a ma jig duet is a fanmade sing a ma jig duet. The big one is orange with the same ears as the hot pink sing a ma jig, green and blue hair, orange star eyes, a nose that's the same color as the rose sing a ma jig and a mouth that is the same color as the little one from the royal blue duet. The hand is the same same as the birthday ones, and the feet are the same as the teal. The little one is hot pink, has star eyes which are colored the same way as the eyes of the Hot Pink one, ears which are shaped the same as the Pink Sing-a-ma-jig, is pink, a blue nose and a red mouth. It has the same hand shape and pose as the reindeer and the same feet as the ghost. They sing "By The Light Of The Silvery Moon". This duet is the 2nd one to have the big one holding a bunny. 
4. Tangarine with Hot Pink bunny

This is what they look like.

Here is what their voices sound like.

Big one: Big one from the Plum duet (Signing on, going to song mode and signing off); Mermaid (singing, harmonizing and chatter)

Little one: Rose (whilst harmony is the same notes as Mickey, signing on and signing off the same way as the big one from the Sea Green duet)

Here's their entry of song mode, sign on and sign off.

Sign on: Both (at the same time): "Hello!" 

Song mode: Big one: Song! Little one: Sing it.

Sign off: Both: "Bye Bye!" (Big one first)