If someone you know constantly makes reproductive anatomy or other borderline jokes and you think they should stop just play dumb. After the joke just say (with a straight face) that you don't get it. When they have to explain it it the joke satisfaction is gone and then more technical words need to be used to explain it making red flags pop up for them and anyone listening. They might get in trouble and you won't need to confront the behavior directly.

Works especially well in the military (even better if it's a superior).