The male talent did something, perhaps arbitrary, but perhaps not. Sometimes they are pros and astute at the vocation, other times they are familiar partners, all but one human. So, she was cumming and encouraging her lover to fuck hard, and it appeared that as she was just going over the orgasm edge, when he slowed from hard , quick, mostly short thrusts, to long, deep , slower thrusts. She completely responded, but it was almost like a reverse edging. That was a nice touch and etched into canon.