So as far as I can tell the rule for deciding if a french word is feminine is “does it end with an e”.
There are exceptions and French people claim that’s not how it works, but it is an incredibly useful heuristic
Ella has a penis. A feminine penis.
Une pene
Une moustache
Un vagine⚜️⚧️⚜️
In spanish “pene” is masculine. However “una pene” (fem) is a much more interesting concept. Even more if we throw in some diminutives. “una penesita”
I actually jokingly call dicks “pussos” with my girlfriend in spanish.
Una pene makes no sense. Also it would technically be penecillo, with a c. However, we do use polla which is akin to dick/cock and is feminine. We also say coño which means vagina and that is masculine
Cimbrel, carajo, picha, polla, tranca, rabo… Tiene nombres mil el miembro viril! (Yeah idk why we have so many words for penis)
It’s a language essential! Dick, willy, cock, penis, shaft, manhood, todger, pole, …