I have always found it difficult to finish if the primary stimulation being given to me is by someone else. I therefore don't find this video difficult to believe at all.
That's because, if I'm not in charge, to some extent, of the stimulation -- either, by being the guy who moves his hips while copulating; or, by being able to direct, or at least to talk, the other person through it -- then I might not finish ever. After a while the stimulation gets painful and my dick shrivels up in an attempt to shy away from any more stimulation. So, it's not "endurance" as much as "lack of the right kind of stimulation." In context of the RIGHT stimulation, I can pop in twenty seconds. Some girls know how to give that to me. I have to train 'em a bit, though ...
My experience has been that generally, although I find that getting a handjob or a blowjob is very pleasurable (of course!), I also find that neither of these services is usually directed properly toward finishing me. Rather, it's pleasurable in the way that a gentle backrub is pleasurable. I've actually fallen asleep during a girlfriend's blow-job -- she wasn't happy with me! but really, if she wanted me to stay awake, she could have learned to give a less soporific blow-job, right? The enjoyment of most blowjobs is "relaxation" of a very very high-caliber, not "stimulation" toward orgasm, and many handjobs tend toward that too.
To continue: when someone else is stimulating me, it's like, the stimulation they give does give enjoyment, but the enjoyment then goes down a different path through the woods, a path that does not usually lead to ejaculation and orgasm. And usually I can't get from one path to the other without going all the way back to the beginning. There do exist, luckily, a few short-cuts in the woods, that lead across the middle of the woods from the wrong (or, non-orgasmic) path, back to the other path and then on to the goal; or, I can always wait a while, go back to the beginning, and try a second time to travel down the proper (or, orgasmic) path from the beginning. But usually, if I get started down the wrong path and then someone forcibly continues to try to lead me down it, as is the case with the determined girl and grandma in this video, then the only thing that's going to happen is, they will continue to force me down the wrong path. And since that path's destination is not the stream at the end, therefore, all that they'll succeed at, is eventually tiring me (and themselves) out. This is annoying, because they get frustrated with how much effort they're putting in, for so little reward (my dick getting softer the more they stroke it, for example); but if they'd just listen, generally, they'd realize that LESS would have been more. I had wanted something gentler, less direct, to get Mister Happy in the mood before just pommelling him like a horse's butt. There's a proper time for the pommelling; too early and you just make pulp.
They do keep at it, the ladies in this video, and eventually they find that all roads through the woods do lead to the stream at the end. But they took the long road. Chances are, if they had spoken with the guy about some of his preferred techniques and feelings, and if he hadn't been so embarrassed and reticent about it, then they would have been able to get him to pop really quickly. One first step, is to not stroke so hard. Back off, be gentle, coax the little shy wood-mouse out of his hiding place, and only then fluff up his fur and play with him vigorously.
At least, that's how my dick has generally worked. I do remember one woman who could just suck like hell -- really, the old golf-ball-through-garden-hose expression applied -- and with her I did go pretty much straight to orgasm, eschewing the wrong path and staying on the proper one. Though I didn't finish right away, but I did finish fairly quickly.
