The practice of orally pleasuring the anus/rectum of another by using the lips/tongue. The 'rim' being the anus hence the act of 'rimming.' Usually applied to those with a fetish for having their ass stimulated in such a way. Also a term used for somebody who is a typical 'suck-up' or 'brown-nose.'
'Man, could you get your tongue any further up Mr. Johnson's ass? He's not gonna give you a promotion, quit the rimming!'
Inserting a handful of Skittles candy into your anus followed by your girl tossing that salad and rimming your ass good. With each swipe of her velvety tongue, you push a Skittle, or two, into her hungry mouth and say "Taste the rainbow bitch!"
12 step recovery jargon referring to someone new who talks about how great life is, now that they're sober. 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.