Prostate Milking Mainstream

In popular culture, prostate milking was mentioned in few times:

1-Road Trip

Movie, 2000

the character E.L. (Sean William Scott) receives a prostate massage from a nurse to produce ejaculate at a sperm donation facility. Though other help was in mind, the audience is led to believe he is immensely satisfied by the alternative approach. The end of the film confirms this suspicion as E.L. directs his girlfriend (Deborah Zoe) to use three fingers for a prostate massage rather than two. This implicates a desire for further experimentation resulting from his previously positive experience.

2-Fargo, TV show, 2014

In Fargo season 1, episode 9. Lorne Malvo's fiancée, Jemma (Helena Mattsson), promises: "Later, I'm going to stick my whole thumb up your ass."

3- Shameless (UK)

TV Series, season 10, episode 7 "Citizen Carl", Aired 2012

Mimi Tutton (Tina Malone) worries Billy doesn't love her when he is unable to ejaculate during sex but Lillian Tyler (Alice Barry)  comes to the rescue. She milks his prostate. 

Lillian Tyler (Alice Barry)

4- The Road to Wellville

Movie, 1994

Nurse Graves (Traci Lind)