Don't let the bitcoin stagnant in your wallet, let it have some transactions. If bitcoins are stagnant the prices will go down someday.
If we just hold bitcoin in our wallet and do not use it, the bitcoin will be useless, so the price will go down eventually.
Supply and demand: the market requires change and transactions to grow.
By not using the bitcoins, you restrict the amount of trading that goes about. If everyone were to stop, then the price would drop down straight to 0.
No demand.
Maybe we first hold most bitcoin and trade with small amount of coins. When the market can absorb more coins, we will hold less and release more coins to the circulation.