I'm going to break this down into The Good and the Not-So-Good to try and keep my thoughts a bit more on track than the first draft of this review turned out.
The Good: This may be one of the funniest genre pastiches I've ever read. Vampire (and other supernatural creature) Romance is a huge market right now, and in 90 pages Evelyn Lafont manages to crack wise about almost every trope of the genre. I haven't even read that much supernatural romance (urban fantasy of the detective/crime realm is more my cup of tea) and I found myself smiling or laughing or nodding knowingly throughout the book. The main reason I enjoyed the book is that it does not take itself too seriously. The book is a fast easy read with lots of funny dialogue and wink-wink-nudge-nudge humor regarding the current obsession with sexy vampires. The author also does a nice job of taking all the standards of vampire lore and giving them the tweaks necessary to make them work in her world without straying too far from what is "canon" about vampires: they drink blood because the magic in their bodies prevents them from making new red blood cells; channels in their teeth draw the blood directly into their circulatory system; drinking blood is an act of sustenance not sexuality; anything that would cause a vamp to lose blood or that would destroy blood cells will eventually kill them (not just a stake to the heart, but any gaping bleeding wound, etc). The main character, Josie, is a bit of a rural rube in her thirties -- almost too innocent despite claims of being jaded -- that is a perfect send-up of the young-nubile-innocent heroine trope. The lead vamps, Gregory and Walker, fit the standard romantic types as well.
The Not-So-Good: Because of the length, there is not a lot of obvious world-building beyond those basics of vampirism, and what other world-building details are mentioned are inconsistent throughout the book. For instance, we are told early on that Vampires are as publicly recognized a minority as any other group you can think of and that laws have been passed declaring that businesses must stay open 24 hours a day to accommodate those who cannot go out in the sun; there's no detail on how long ago Vampires "came out," or how readily they were accepted into mainstream culture. This creates a problem for our main character: vampires are common enough that it's apparently fairly easy to find them, and yet Josie knows so little about vampire culture that she asks incredibly personal questions at the absolute most wrong moments. I realize Josie's questions are a way to get the basic info about vampires mentioned above into the reader's path, but the result is a main character who in social situations is either incredibly stupid (this stuff should be mostly common knowledge and she doesn't have that knowledge despite her vamp-obsession) or incredibly insensitive (she knows what she's asking is a bit personal, but asks anyway, almost like she has no verbal filter between her brain and her mouth). I'm leaning towards the former, because I like the idea of Josie as a play on the young-nubile-innocent heroine and if she's knowledgeable-but-insensitive I don't think I like her as much.
The Part I'm Undecided About: As the book moves from "meeting vampires for sex" to "our heroine is in danger, who will save her" tropes, the plot either becomes burdened with holes large enough to drive a hearse through or becomes a pastiche on the action/adventure genre. i can't speak for the author or her intent, but I have plans to interview her and hopefully will get some insight. I'll post a link when I put the interview up on my website.
Overall, though, I recommend VAMPIRE RELATIONSHIP GUIDE to anyone who enjoys vampire romance fiction and likes a good send-up of genre tropes. I suspect Evelyn Lafont will be continuing the series (otherwise why call this Volume One) and it will be interesting to see how she maintains the tone of this volume.