My view is there's no absolutes with JAV. Is anything always fake or always real? No. The pix you pasted contain many fake photos. In the sense that these pix were shot separately with a photo camera, not frames from the video shooting. So I think what happens is during the filming, there are sessions (like 30+ minutes continuously) of video-taping, with the studs and idols doing whatever the "script" needs. And in between they might switch to "photo mode" when they arrange the scene (which may resemble the video footage but not necessarily fully. During photo mode, I guess 90% of the time, the sperm and/or ejaculation are fake. That's why when you watch the vid, you rarely find the quantity and gooeiness and milky/creamy color and powerful jet-stream of cum that you see on the official promotional photos (esp. your second to last pix, double jet-streams that has enough momentum to bounce off idol's face after shootin up against gravity for some 10+ cm, no guarantees but if I bet, I bet fake: fake penis, fake sperm). It's a scene set up purely to get a good still photo, not a continuous video footage.
If the cum is shot on idol's face, chest, or butt, then probably why not? Good chance it's real. If the ejaculation is insider idol's mouth or pussy, then... I get more suspicious, if she spits out or pussy oozes out a lot of sperm, I think fake; if it's unimpressive, I might believe it's real.
Not an absolute rule, of course in real life, each man and each time, the cum shot and the cum itself varies. So it's unfair to say impressive looking ones are fake, and unimpressive ones are real. I myself care much less if it's real or fake, I care more if the scene looks good or not.
