Buy RXD ..
https://www.proshares.com/our-etfs/leveraged-and-inverse/rxd
If you have a specific stock in mind .. you can always but PUT options .. PUT means you buy the right to sell stocks to someone at a strike price before a strike date ..
Well, that simplifies it... Thanks. I'm still curious how to short stuff though. I think I used to know, but I've had some memory loss.