This trick allows you to use improved poisons (from talents and 3 bloodfangs) even if you dont have improved poisons or 3 bloodfangs..
Normal instant poison got 20% chance to proc.. with talents it got 30% to procc.. and 3 bloodfangs 35% to proc..
What do you have to do
Get 3 bloodfang, and improved poisons at your talent tree.... (every improved poison thats posible in talents) and then make _ALLOT_ poisons..
Why ?
Because you made the poisons while you had a talent on it.. you could give it to a friendly rogue and he will be able to use the improved poison, even if he dousnt got 3 bloodfang or talents on it.. He will see that his instant poison only got 20% proc chance.. but if he uses it and use a special damage meter you`ll find out that it has procced around 35% times..