Its funny.. whenever I've met a woman who's claimed someone has a small one. I've always seen it as a reflection of their own paranoia. After all medically the standard deviation is fairly low unlike boobs for example
Any man suffering from a small one (mirco penis - medically) may actually be suffering from low testosterone. So Its possible that aggressive and fast male drivers may actually have bigger than avg. tackle.
Conclusion - most men will see this for what it is. Do they actually think men speed to impress women? More likely they are just driving normally and safely at the correct speed for the conditions.
its rather sad really - I don't think speeding will ever be socially unacceptable until we get back to setting speed limits in-line with the 85th percentile