>>89509324penis size is independent of height outside of growth disorders (such as certain kinds, but not all kinds, of dwarfism related to hormonal development problems) and, up to a point, independent of muscle mass
that point is when you have so much muscle that your hormones are all fucked up and your penis (and testicles) actually shrivels because your cells think it's not needed (by comparison to building muscle)
it will not grow back just because you stop taking the roids
tl;dr Colossus probably can't even get an erection, and judging by that image, Cyclops isn't far off eunuchtown
likewise the depth and width of the vaginal canal is independent of height, and "virginity" was prized because the cavemen didn't understand about kegels, or indeed any sort of deliberate exercise
but to answer your question seriously here, it's X-23 because she has the most psychological damage, meaning she's the most likely candidate to suffer from vaginismus, which is an unconscious contraction of the vaginal cavity related to stress
in fact you probably couldn't get your finger in, and if you did, she'd crush your bones
