The Joy of Sexual Physics

                                                                        with Dr John

 "Love is a matter of chemistry, sex is a matter of physics"


Q  My boyfriend, Albert, has an endowment problem such that having sex with him resembles being penetrated by a small, wet noodle. Given my disdain for Maggi and my reputation as a big pussy, is there anything I can do to deal with this situation without putting pressure on his performance?


A  In a delicate situation such as this one, you must be very considerate of your boyfriend’s emotions. Suggesting various methods of penile enlargement such as vacuum pumping or laser phalloplasty could cause him feelings of embarrassment and inadequacy during sex. Rather than solving your problems, this could lead on to erectile dysfunction or premature ejaculation. But fortunately, there is another technique that can improve your sexual compatibility without your boyfriend actually doing anything at all.

The basis of this technique is in the relativistic theory of length contraction. In a previous response to a similar question, I approached the idea of relativistic sex by assuming that your boyfriend was oscillating on top of you, reaching a speed infinitesimally close to the speed of light for most of his upwards and downwards motions. However, rather than solving his endowment problem and improving his stimulation efficiency, this scenario led to your boyfriend’s penis getting shorter and shorter as he sped up (until at the speed of light, it appeared to have no length at all).

But this process is easily reversible; and if we instead assume that your boyfriend is beneath you while you oscillate up and down on top of him, then the length contraction will occur in the depth of your vagina, rather than in the length of his penis. So while your vagina is happily travelling along at close to the speed of light, although you will still perceive it’s normal dimensions, he will perceive it to be much shallower than usual. And since your boyfriend will still perceive his penis to have its usual length, this apparent vaginal length contraction will lead to a much more compatible fit. This compatibility is satisfied in both reference frames, because from your point of view, although your vagina will still appear to have the same length, your boyfriend’s penis will appear to elongate.

The extent of this relativistic penis elongation is actually quite an important factor; because if the penis is too long, it won’t fit; but if the penis is too short, it won’t give the desired penetration. So to satisfy this delicate balance of conditions, there is actually a relativistic mathematical equation that can be applied, whereby the extent of penile elongation depends on the speed of vaginal thrusting. Suppose that the usual length of the erect penis is given by LP, and its desired length is given by LD. Then the required speed of vaginal thrusting is given by v, where v = c(1 - LP2/LD2)1/2, and c is the speed of light. For example, suppose that your boyfriend’s penis is an inadequate 12 centimeters long, and you desire a more penetrating and sensual 19 centimeters; then the required speed of vaginal thrusting is approximately 180 million metres per second. To put this in perspective, this corresponds to about 1.11 nanoseconds for each oscillation, or about 900 million oscillations per second (in the unlikely event that you can last that long).

So what you will gain in length and compatibility, you will lose in duration. Admittedly, this is not a perfect solution to your problem, because it will unavoidably lead on to other problems. And because twice during each oscillation your vagina must decelerate, stop and accelerate in the opposite direction, there will be two brief moments in each oscillation during which your vagina will revert back to its normal length. As a bizarre consequence of this, your vaginal depth will oscillate regularly and frequently throughout intercourse, and correspondingly, so will the stimulation from your boyfriend’s penis (this phenomenon actually does occur during any sexual intercourse, but generally only occurs to such a small degree that it is undetectable). Furthermore, because length contraction and elongation only occur in the direction of travel, this technique will not enhance the diameter of your boyfriend’s penis (which is arguably its more important dimension).

But despite these shortcomings, when performed correctly this technique will enhance the length of your boyfriend’s penis for the majority of your sexual activity. At some point he may question your motives for such high-speed motion during intercourse. But if he does, just tell him that you love being with him, and that this love is independent of his penis size, but that according to the theory of relativistic length contraction, by attaining a sub-light relativistic speed of vaginal thrusting, his stimulation efficiency will be greatly enhanced.

In addition, you can do pelvic floor exercises to strengthen your muscles and give you more intense orgasms. Seven minutes a day should produce the desired results within a week.

Got a problem, or even just a question?
Pour it all out to John.
Since the end of the twentieth century, Dr John Marshall, Ph.D. Sexual Physics has been a sex and relationships writer taking the little-known sexual wisdom from the ivory tower realm of the theoretical physicist to the layperson.
Feel free to write to him at [email protected] or you can visit his webpage at

© John Marshall, 2003