A college co-ed who drinks at night and lays in bed/couch during the daylight hours venturing only from her cloister to receive delivery pizza, natty ice and a new box of condoms. She will eat, drink and fuck in her cloister until it is dark and time to go out again.
CK- "wow, I feel like I don't get out in the daylight anymore"
You- "Yeah, thats because you are a cloister kitten"
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.