My friend, let me give you an advice: if you want to talk to a woman about penis size, hire an hour with a popular, high class hooker on your region. Preferably an intelligent one (you can look at rating sites for hookers or have a little chat with her before the meeting to evaluate that). Some of the best talks I've had about this subject were with women of the life. Some even told me I was honestly the biggest one they ever had, and that feels great! One quote that stuck with me was: "you have the dick that every woman dreams about but is also scared of at the same time" lol
If it's against your principles, you don't even have to have sex with them, just talk and/or have a (legitimate) massage. It's a service they offer that's more common than you think. Consider it like a therapy session lol.