5
Homebrew item : bottled inspiration
(ttrpg.network)
A place where Game Masters, Dungeon Masters, Storytellers, Narrators, Referees (and etc) can gather and ask questions. Uncertain of where to take the story? Want to spice up your big baddie? Encounters? That player? Ask away!
And if you have questions about becoming a Game Master you are most welcome with those as well!
Rules
I think it's a good idea, not dissimilar to WBW's Potion of Advantage. Ultimately it's up to you, as it is every DM, to decide if you want players to be able to stack inspiration in that manner, but as you pointed out, allowing players to stock inspiration tends to discourage them from using it unless they have a stockpile already, because they don't lose anything from not using it.