This is an old school term that I am very surprised that isn't on here. When one thinks they have come of age or at a stage in they life that that they can talk and act a different way towards others...mainly seen in a negative connotation. The term is a reference to one's bodily changes as one gets older: what one eats and drinks as they get older can change the actual smell of one's urine as it becomes stronger...
Smelling your piss: alll of a sudden he thinks cuz he got that job up at UPS and he makin' a lil money, he can get funky wit his momma and them talkin back to them like they aint shit...over there smellin' his piss
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.