Watch as Nikko pees in her pullup until it starts to leak in this video.
As the video starts we are treated to Nikko wearing absolutely nothing but a pullup style diaper. Then, standing in front of the camera, she proceeds to pee in her pullup. We can clearly see her diaper expand as it fills with pee, eventually overflowing as a trickle escapes down her leg.
Once she is done peeing she takes off the diaper and holds it up to the camera. She managed to squeeze out some of pee and pour it from the diaper onto the floor.