Smellervation 

Derived from the word "observation" but this is performed with your sense of smell and not your eyes.

I've made a smellervation that my neighbor is having BBQ for dinner... the whole street smells delicious.

Smellervation by Chevyguy75 September 9, 2018

Smellebration 

Smellebration is when you walk into someones office or room and give them an air sample of last nights dinner. A large fart that is so bad they try to choke it up.

Walked into Brads office today and had a smellebration, he could not run away fast enough it was such a bad fart he could taste it.

Smellebration by Nelppik April 30, 2010

Smellebration 

Usually on a long car journey, or other prolonged period of confinement with friends, the grudging acknowledgement that someone has dropped the most rancid, evil-smelling shit so far.

Whilst the victor - or "he/she who dealt it" - can remain anonymous, they can usually be be identified as 'looking happier than a wanking Jap' at their achievement.

"I think a smellebration is in order, but Jesus fucking Christ, Dave, something has crawled up your arse and died. Get some medical help ffs."

Smellebration by Kart Yoda February 6, 2019