A hybrid of yesterday and tomorrow. The two cancel each other out, so in the end you just have an unnecessarily elongated form of today.
Employee: "How are you tomterday?"
Customer: "I was doing just great until you fucked everything up by using tomterday. By the way I need a pack of condoms."
12 step recovery jargon referring to someone new who talks about how great life is, now that they'resober. Usually meaning that the person is out of touch with reality.
The new guy seems pretty happy for a dude who has no job, no money and no family. He must be on a pink cloud.