lol
Chess Celebrations when to fist-pump.
5 Tournament win – Here I get really excited. Unfortunately I black-out so I can’t remember a thing about it - I just have the cabinet full of trophies as mementoes.
Repeated black-outs are a symptom of being possessed by Lord Voldemort. Have you or any of your friends been near a giant snake recently and/or reading a magical diary? If so, contact a local physician immediately.

The black-outs only occur after the tournament wins. As a fully functional adult I do not read children's books so I know little of this Lord Voldemort of which you speak.
I always throw my fist, often with several pieces, in the air. I may even be using my psychotic celebrations as an advantage: people are desperate not to let me celebrate so they overpress and lose.
Under Welsh chess convention it is considered poor etiquette to throws pieces in the air
But everything else is good etiquette?
Their is no etiquette in chess. Either you can do it or you can't. If you can and it helps you, you should. If chess is a game then the best players are gamesmen.

As a strategic move beast, could one fistpump with a slightly less than normal volume "Yesss" EVERY move your opponents makes? Perhaps add a lowtoned "hahahaha" every third or forth move? I imagine OTB opponents would often become self-conscious and resign somewhere in the middle game.
Chess is an ancient game of wisdom and decorum of mutual respect and intense competition so what is acceptable when it comes to releasing the passion and emotion in celebrating your hard fought victories?
I have a gradated scale of chess-related celebrations for my key moments over the board which you could use as a guide:
1 Capture a pawn – seated fist-clench (right fist) with a “Yesss!” hissed discreetly under the breath. No eye contact.
2 Capture of minor piece – standing fist pump (right fist) with a loud “C’MON!” Keeping eye contact.
3 Capture of Rook or Queen – Standing double fist pump one foot on the table (not the board – this is Chess not football) full eye contact from a range of less than one foot high volume: “WHO’S THE DADDY? WHO’S THE DADDY WHO’S THE DADDY?”
4 Checkmate – Standing on the table (not the board) full hip gyration both hands raised to the heavens full volume full eye contact “I AM GOD! I AM THE CHESS GOD!” Back-flip dismount to touching foreheads eyes almost in contact still full volume “PRAY TO YOUR MASTER! PRAY TO THE BEAST! YOU ARE THE LOOOOOOOSERRRRRRR!!!”
5 Tournament win – Here I get really excited. Unfortunately I black-out so I can’t remember a thing about it - I just have the cabinet full of trophies as mementoes.
I wonder what celebrations you use in your matches both OTB and online?