Sure, the proposition that "penises are vaginas travelling faster than the speed of light" is perfectly coherent. Vaginas and penises are perfectly well-defined, and the notion of a penis travelling faster than the speed of light is, while not considered possible by any existing physical models, is entirely logically sensible.

It remains to determine whether vaginas are, in fact, penises travelling faster than the speed of light. The short answer is no, since anything travelling faster than the speed of light would be travelling faster than the speed of light, and vaginas typically travel subluminally. Thus, we have proven this well-formed statement false.

Now we're getting somewhere!