>>50347436in is fine. With that size you can hit her hard without any worries. Most of women are much more sensitive first few inches, so that doesn`t really matter much. Quite often guys with 8in has to deal with such problem as short vaginas. They can`t make full push and proper bang becomes minor pierce. Not only they can`t shake her ass and pubic, they also has to control how deep to move and not to make it painful. Do you wanna to constantly control how deep to move during sex? But dick has to be thick. Yea-yea, women can train muscles and to squeeze even pencil, but do you think they really want to do that every time? It has to move whole her insides and be sure, women cums much stronger and more with thick dick.
It`s really all about ego. We see absurdly huge dicks in porno, but we always forget about queen sizes of actresses. They can fit few dicks in same hole without problem. Now go to your girl and say you are going to fuck her with dildo alongside and see how round of terror her eyes becomes and how fast you would hear "No-no, no sex for you".