This works only if you have a margin account. Majority have cash, and that's not a choice, broker will loan it to shorts whenever they want. Don't trust me, go verified with your broker.
But I do like MAGS eventhough it is too 'cooked' up when it spiked to $40 (thanks to TASR and people's hope to have TASR like performance). They should have sold at $36-38 when price action stagnated.
I am waiting for the bottom to form, and it will form pretty soon. A solid bottom will be tested several times and eventually settling, unlike a false bottom of $28 that many claimed. Guessing there will be a lot of limit orders for $18-$19. But realistically, $20-21 is a good buy after a 40% retracement. Sorry for all the ones that lost a fortune, I have been there this year myself.