You sell a percentage of your (Bitcoin) for (cash) each time-period, and you buy (Bitcoin) with a percentage of your (cash) each time-period. You can put any tw

You sell a percentage of your (Bitcoin) for (cash) each time-period, and you buy (Bitcoin) with a percentage of your (cash) each time-period. You can put any two assets in the parentheses. You end up having a balanced ratio of assets according to the relative ratios of those percentages and the current value of each asset, and it will be balanced at a rate according to the total percentage you're trading on (10% means it'd be averaged over 10 time-periods). There is more formal analysis of this by people around optimal portfolio theory, math about how to balance your portfolio among a variety of assets to choose a risk level analytically, but this is the rule of thumb version AFAIK.