TL;DR lots of USD swaps (longs) means a lot of people holding BTC with borrowed money in hopes that BTC will go up so they can sell and pay back the $$$. But they're paying interest daily, and if market goes down too much they might have to sell their BTC before loosing everything, or if it goes down too much the BTC might be sold automatically by exchange in a margin call. Which might cause a domino effect. Price falls, person 1 gets margin called and his coins are sold on the market, causing the price to drop even more, now person 2 gets margin called and now his coins are market sold driving the price even further down now person 3 is in trouble etc...
BTC swaps (shorts) are the other way around, people borrowed coins, sell right away and sit on fiat. Eventually they have to buy the coins to give them back (close their short). They obviously hope to rebuy at a lower price. You borrowed a coin from me at $1000, price goes up to $5000 but i don't care and want my coin back, so you're forced to buy at the market price. Forcing price up, and possible margin call on other shorts driving the price even higher...
BTC swaps have more than doubled to 18600 from the recent low of ~8500 on 24th October
Historically speaking, it looks like bubble territory for the shorts. Backed up by the fact that longs are at $20m which is a third off the july/august high of $30m when everyone was trying to catch the bottom.
Max pain incoming....