Just use your discretionary funds to get into bitcoin investment as that's the most simplest form of not getting panic or feeling emotional about risking losing your funds whenever it happens that a whale or an institution sold big chunk of their bitcoins. The panic is mostly out of the fact that the investor is risking what they can't afford to lose, because you can't move funds meant for an important project into bitcoin investment and peradventure the market price starts falling and you don't get to panic, it would be rare not to.
What money can we actually afford to lose? Truth is nobody wants to lose money. That's money we worked damn hard to earn in the first place.
When people say to invest discretionary income, that doesn't mean you gotta go in already accepting you'll lose it. It simply means it's money left over after you've taken care of the essentials.
And even investing with that spare cash, the anxiety ain't just gonna vanish completely. Fear's just part of being human, and what we actually need to do is learn to manage it. Build up your knowledge, have a plan for different scenarios, and invest only with that spare money like you said. Do that, and you're much less likely to panic and make a bad call when the market goes against you.
You've just buttressed it in different words yourself and I think you understand what I mean by what I said in first comment. After all essentials has being met and what's left is the funds you can use to do anything you wish, equally as you can use it for pleasurable activity since essentials has being taken care of, so it's definitely not money that can make you catch cold should it be lost onto investment, that's why I consider it as funds a person can afford to lose.
Spare cash is still money so whatever happens the investor might still feel the loss, no doubt at that, but such loss can't be quantified to when you use funds that were supposed to be projected into some essential course that needs to be done. The anxiety and grieve at loss would definitely be different.