In which Primo wants to talk about his dad's man parts and I get sick to my stomach

Primo: My dad says he regrets letting them circumcise me and my brothers.

Me: Well, I do think it's mutilation. If we'd had a little boy, I would have been against it.

[More conversation about the issue, pros and cons]

Primo: Maybe it's not such a bad thing. My dad [who is, I gather, not, which is far more than I want to know about that issue] says that he has problems with -

Me: Stop! I do not want to hear about your dad's [parts]!

Primo: But -

Me: No! I mean it! DO NOT TALK ABOUT YOUR DAD'S [PARTS] WITH ME!