Actually look closer. She’s squeezing the underside and effectively clamping the urethra down as he cums. Guys, don’t let a woman do this, some have learned this trick to control how much pumps into their mouth during ejaculation and by stopping the flow, it causes backup into the prostate. If done wrong or on a regular basis, the guy will wind up with a prostate issue, likely acute prostatitis. In other words, don’t do this!