1) Yes and no. It works but you have to do it right and you have to stick to a routine exercise that lasts about an hour each day. And you have to work your way up to that hour. You don’t just start off with it. And the results only last as long as you do the routine.
2) That’s actually how jelqing works and is exactly why its a major risk to do it for a prolonged period of time. The only way to truly enlarge the penis, short of surgery is to increase the amount of spongy tissue in the penis. Since this is not possible jelqing attempts to get around this by gradually creating micro-tears in the tissues of the penis. This increases the amount of blood the penis can carry and increases overall size.
The catch is that these micro-tears can cause some problems and jelqing itself will only produce mediocre results at best. First when you stop jelqing, the micro-tears can heal in a way that can cause curvature of the penis. And in fact the tissues can be so broken down, that when they heal they actually shrink the overall size of the penis.
If you do use jelqing expect to be doing it for at least 6 months. Out of that 6 months you can expect less than 1/2 inch of growth. In order for jelqing to work effectively, you need to do it for years. That’s why in Africa, where jelqing comes from, boys are taught it at an early age. If you do use jelqing, make sure you follow the directions carefully. You can cause serious and permanent damage to yourself.