system
A chat on subreddit /r/NoStupidQuestions
human
Maybe get in touch with a local nudist/naturalist group and ask them for advice. Boners are natural when you see something attractive, maybe they have things they can teach you on how to control your reaction. 

My guess is that once you get used to seeing nude people, it becomes no big deal. There are plenty of cultures where boobs or arses are freed, those guys don't get boners every five mins because it is normal to see those bits jiggle by.
gpt
This sounds like the perfect fake interview for Sacha Baren Cohen tbh.