I'm almost certain that the creampies in those SDEN vids from SOD with creampie/fan-appreciation theme are real. There are a lot of one-takes and the "fans" nut really quick (some do it less than one minute - like how it should be when you are an amateur fking a JAV actress). Some examples are: SDEN-001 and SDEN-032 (the latter is best in the series IMO). They remind you a lot of MOODYZ' fan appreciation vids.
Or Taiga-Kosakai is just extremely good at faking those shots. If the pixelation could be any finer, some of the vids in these series could top MOBSTER's or KV's creations because SDEN-series vids just have better production values.
BTW, I like Knight Visual but I *hate* it that I almost always have to see the actors' butt when they cum because of how the cameraman operates. Related to that, they also need to introduce more variations to their upcoming works because it's getting stale.
*added sden-032 cover