Open interest counts contracts outstanding. Price you already have. Move both over the same window and you get four combinations, each saying something specific about who is doing the buying.
The four boxes
Price up, OI up - new longs. Fresh leveraged buying. The trend has fuel, and it has also just created a fresh layer of liquidation levels below the market.
Price down, OI up - new shorts. Fresh leveraged selling. Squeeze risk is accumulating above, because those shorts have to buy back if it turns.
Price up, OI down - short covering. A rally driven by positions closing rather than opening. It is weaker than it looks and tends to stall when the covering finishes.
Price down, OI down - long liquidation. Forced selling rather than conviction. Often violent and often brief, because the sellers are being removed from the market rather than choosing to sell.
Using it honestly
The quadrant tells you the character of a move, not its direction from here. Short covering and new longs both look like green candles; the difference is whether anyone is left to keep buying.
Two cautions. Use a window long enough to mean something - eight hours works well in crypto, where funding intervals set the rhythm. And read open interest per venue before you aggregate, because a single venue with bad data can invent a regime that is not there.
The Crypto Market Map computes this per coin, and withholds it where the venue data does not agree well enough to trust.