Earlier quoted context omitted.
i run a bootstrapped company that i founded in 2006, and i have some extra money i am totally comfortable of losing entirely. i view this as an experiment. i am looking for a serious practical advice.
Consider this carefully: "When you are a long a stock, the most you can lose is the amount you paid. When you are short, you can lose unlimited money." If you have "funny money" that you aren't afraid to lose, there are safer and more responsible ways to experiment with the market than unprotected short positions. You may want to read about and understand some options strategies: http://www.investopedia.com/terms/b/b…
If you're looking to play around with some money - basically playing a gambling game with companies - then options are a fun little game and you can manage your downside perfectly.