When your boss asks you to do something and you know you should refuse but you do it anyway you are "Sniffing the chair"
"So, this woman who came to work so intoxicated a couple of years ago she lost control of her bowels and bladder in the office" My boss made me sniff the chair to see if it needed to be thrown out. "Sniffing the chair
pertaining to when a person smells a package of cold cuts (or leftovers) to ascertain whether it has gone bad, and when finding that it has indeed gone bad, continuing to smell it, resulting in vomiting from the smell.
i can hear dad sniffing lunchmeat from my room. he obviously does not mind puking afterwards.