So it's basically either one or the other, right? No "in between".
A bit sad there isn't an option to resize the schlong.
Every thinkable body part can be customised in great detail but that one fails...
And here it's way overdone if you ask me.
On another note:
I've ran into the problem where it happened that one of the girls asked to get physical. Upon answering "no" the "yes" dialogue showed instead and the h commenced. That honestly annoys me at times.
O, it doesn't concern girls with the dominatrix trait btw. Those don't even ask, they command (like they should).
Funny thing with them is that when she demands it and you cancel it at the first possibility, she still thanks you as if she got the 'real deal'.

(That, of course, doesn't lower her lust so she'll keep mounting you if you're lying in bed (for instance).