Why D&D isn't the best system to use for roleplaying sex with gnomes

The Book of Erotic Fantasy is a recent RPG release from Valar Project, Inc. It adds sex to D&D.

As such, it includes rules for maintaining sex (roll against your Constitution), details on what Elves, Dwarves, Gnomes, and even things like Centaurs think about sex. Things like this:

Like dwarves, the genetic makeup of gnomes prevents them from producing halfbreeds, unless the other parent is a celestial, dragon, fiend, or other being noted for its ability to successfully crossbreed. This does not prevent gnomes from sampling sex with other beings-indeed the idea that they cannot get the other creature pregnant is more than a bit enticing.

And yes, it's geeky as fuck, but it's relatively harmless.

Some bits are, however, inherently broken. Never mind that page 133, according to the table of contents on their website, features a sidebar "Alternate Spaces for Magic Items on the Body". Consider the Prestige Class Sacred Prostitute.

Requirements
To qualify to become a sacred prostitute, a character must fulfill all the following criteria.
Base Attack Bonus: +3.
Charisma: 13.
Appearance: 13.
Feats: Sexually Open Society
Skills: Diplomacy 8 ranks, Perform (sexual technique) 8 ranks, Profession (prostitute) 8 ranks
Special: Must be willing to engage in sexual acts when asked.

Table 3-15: The Sacred Prostitute

Class Level	Base Attack Bonus	Fort Save	Ref Save	Will Save	Special
1st	+0	+0	+0	+2	Aura of Sexual Ease	0 - -
2nd	+1	+0	+0	+3	Sexual Healing I	1 - -
3rd	+1	+1	+1	+3	Sexual Communion	1 0 -
4th	+2	+1	+1	+4	Sexual Healing II	1 1 -
5th	+2	+1	+1	+4	Restorative sex	1 1 0

The very first thing it mentions is that you need to be able to hit things fairly well to be a prostitute. And if you get good at it, what do you know - you get even better.

That just plain does not make sense. You should not be able to become a fine fencer by dint of shagging people. I see no reason why learning one skill automatically gives you the other. But this is D&D, which has its origins in wargaming, and it is axiomatic that when you go up in level, you get stronger, harder, and better at hitting things.

Even if you're a Voyeuristic Seer.