It's mathematics slang for cutie pie. Seeing as 3.14 is the value of pi, well actually 3.141593 is probably closer even though it's an infinite number so 3.14 will do, but yeah you can catch my drift.
Usually in a text message or written/typed message of some sort:
Guy 1: Did you see andrea?
Guy 2: Yeahhh! She's a QT 3.14
Guy 3: lol i see what you mean. lol.
Cigarette: Northern slang for a cigarette, used oft by mashed up mancunian ravers becasue of the resemblance of a hot(electric)stove to the end of a lit cigarette. Originated circa 1991 in the early halcyon days of the rave culture; we speculate during a drug fuelled hallucination by said manc.
'fuck me noel, i am bolloxed, is that a ciggy in your mouth, or the stove from me 'nans kitchen'/
General use: 'Give us a stove you cunt'