Immediately after you go over the edge and you know that you can't hold back the orgasm any more, stop all stimulation and try one of the following:
-Tighten every muscle down there as much as you can and hold them tight for as long as you can.
-Release your hand and don't touch anything until the orgasm is over.
The orgasm will probably be less pleasurable than normal, and you won't ejaculate as much as you normally do (You may not ejaculate at all), however, if you did it right, then you can probably start stroking again (gently and slowly) and remain hard and be able to have another orgasm within a few minutes.

If you're finishing too fast with an FL, have you tried varying speeds? Slow down or stop when you feel you're getting close. You can't just go jackhammer speed the whole time and expect it to last. Also, tightening the muscles down there will probably help.

I've done that before. The experience is usually so intense that it doesn't need any extra tips. It stands quite well on its own.

Yes. Fleshlights are that good. I've used one practically every day since I bought my first probably about five years ago, and that first one is still in good shape. I like the Speed Bump texture, but pretty much anything except the ultra-tight is good. The orifices don't make all that much of a difference, so pick the one you like the look of the most. Yeah, the price can be a bit steep, but when you consider that it feels better and last longer than other toys, it's worth the investment. You could easily spend twice as much blowing through cheap toys that keep falling apart.
I'm cut and don't find it unbearably intense. I find it much easier to edge with one because my hand doesn't cramp up, it tends to retain lube better than my hand, and there's less mess.
Men in Fleshlight videos do pull out for the cumshot. Unless it's an Ice, finishing inside an FL would make for a boring video, because there's nothing much to see. When not making a video, I almost always finish inside the FL. It feels better and it's easier to clean up.

I wasn't all that impressed by the Tenga that I tried. The material didn't have the right amount of give, so it didn't feel all that great when I was stroking.

I like the Aneros, but I hardly ever use them. I guess I don't like the cleanup, and they seem to take more effort. I don't have any that are comfortable to sit with and I've never tried any of the modifications. I've also never had a "Super-O" that some have described, although they definitely do enhance the sensations and pleasure. Pre-cum typically starts flowing almost immediately after I insert.

I'd also recommend a strong cock ring vibrator. Not those wimpy watch battery powered disposable things, but the 2 AA battery powered strong bullet vibes they have. If you put one of those on just the right spot, you can ride it over the edge without even having to touch yourself.

http://www.xtube.com/watch.php?v=L8WqM_J729_

I have one. It's not all that great. The vibration is very weak, it was awkward to use, and the ring didn't stimulate me that much. It didn't want to glide smoothly, it sort of gripped and yanked. I only used it a couple of times.

1) Pretty much all the time. Ever since I learned to take it slow, I rarely ever race to the finish anymore.

2) 30-60 minutes. Sometimes I'll go for two hours, but that's rare. I've never tried to go all day, I've never seen the point.

3) Yes. Once in a while I think that I should try doing the edge and stop thing for a week, just to see what it's like, but I never go through with it.

4) I try to keep it at a fairly steady level of pleasure just below the edge, but not hitting it and having to back off all the time. That seems to work well for me and the pleasure builds as I go.

5) Usually I'll keep it right against the edge for only a minute or two. I think once I managed to hold it for ten minutes of pulsing, twitching ecstacy, but that's rare.

6) Slow strokes, applying pressure around the head, with some assistance from tensing the PC muscles in the right way.

7) I tend to stroke as long as I can, but usually sometime around the first contraction, I'm unable to keep at it. Partially, it's because I become too sensitive, and partially because I'm physically unable to keep stroking.

8 ) The right level of relaxation, the right level of lubrication, the right temperature, the right mindset...

9) It is usually rubbing my nipples, stroking my balls, rubbing my stomach, or caressing my perineum or the lower section of my shaft.

10) Into a Fleshlight, for easy cleanup.

11) Lubed, definitely. Doesn't really work for me any other way.

12) I use a Fleshlight almost every time I masturbate. I occasionally use a strong vibrating cock ring or an Aneros.

The paper needs to slide freely for this technique to work. Pretty much any amount of wetness will cause the tissue to stick to the penis. Even wiping it away still leaves a wet spot at the tip.
Although, I must say, this was the reason I first tasted it...

I used to use tissues and toilet paper too, but in a different way. I'd wrap them around my penis, then hold it and stroke normally. With the other hand, I'd hold another tissue or a few squares folded up and ready to catch the cum. Almost no mess and no evidence. When I was done, I'd flush everything.
As I got a bit older, I started leaking a bit of precum which would cause problems if it got on the tissues.

First of all, turn down the vibe. I've found vibes on full speed to be more irritating than exciting, at least to start.
Next, set aside some time for exploration. You'll have to learn how your body responds and find what works best for you. If you just rush in, racing toward the orgasm, you'll never find what you're looking for. Hands off your cock and focus solely on what you're doing with the toy.
Finally, go slowly. You said you "went to work", which makes me think that you were using the toy like a jackhammer. Prostate toys usually work better when held in place against the prostate, rather than rapidly thrust in and out.

What was the toy you got and how were you using it?

I've never had a full on prostate super-orgasm myself. Anal play just seems to enhance and intensify the sensations and pleasure, but it's never been an earth-shattering event for me.

An Aneros is a anal toy designed for prostate stimulation. You use it by putting it in and leaving it there. It's not meant to be moved around like a dildo.

Yeah, I have a couple of the different sizes. They do increase the pleasure for me, but I've never had one of those "Super-O"s that people talk about. It does greatly increase my precum flow, though. Sometimes I'll start dripping almost immediately after putting it in.

The watch battery ones are usually too weak to be of any use, anyway. That's the reason I avoid them. Also, they typically only last about 20 minutes.
I don't know of any that just take a single AA battery, like on the ring. There are plenty that take two AAs in a battery compartment that's wired to the bullet. They've got great power, and you can use rechargeable batteries in them. Sometimes I can get off hands-free, just using one of those vibrators.

$140? Where are you looking? They're $65 on Fleshlight.com, if you get one of the Build Your Own options like a Wonder Wave or Speed Bump.
I don't think they magically fix stamina problems on their own, but they might help you learn how to last longer. I'm able to go a long time with one, mainly because my hand doesn't start to feel cramped after a while. I think people claim they're good for stamina because they feel better than a hand, so if you want to last longer in one, you really have to train yourself how to.
Really, though, the trick to overcoming stamina issues can be learned anywhere, it just takes practice. The key is to know when to slow down or stop or clench your PC muscles. Don't just go jackhammer speed in a race for the finish. You have to be aware of your body and know when you're close to an orgasm and adjust what you're doing accordingly. A sex toy is a good tool to help you learn that skill, but by itself, it will do nothing. You have to work at it, or you'll still be a minuteman, even with an FL.
Now, that said, I really enjoy my FLs and think that they're definitely worth the money. I use mine pretty much every day.

Before shelling out that kind of cash, have you tried a cheaper cock ring vibe? (One with a full powered bullet vibrator powered by AAs, not one of those wimpy single use watch battery things.)

I'll slow down for a while or stop for a few seconds. I never do the squeeze method, because I don't like the way it feels and it never really worked. I will tense my PC muscles, though, which helps hold off the orgasm. Tensing the PC muscles is also how I have multiple orgasms occasionally.