I especially get suspicious when they don't open up the breasts to show the cum glazing, or when the camera begins to pan up like there trying to hide that they're pulling out the device for the fake shot. You will see a lot of fake ones in these code series RCT and BOBB they'll have real and fake interspersed throughout, I'm very surprised you see some in the PPPD series, i didn't think they did that, maybe they're getting lazy, and started to think faking it is easier.
I also like Yuria Yoshine, i have her on my list of actresses to search for finishes for.