For when someone means it so much that they are the only person to have ever done such a thing.
To such a point that they would climb the Mountain Everest just to prove such a point.
“I LOVE YOU MOSTESTERER”
“Love you mostest, that’s top of the tier list”
Nope, mine has that in it. Mine has that plus 2”
“IMPOSSIBLE. THATS NOT A WORD”
“Just made it one