I'm seeing some strange things with your home-page, even looking at your indexed pages (i.e. with the site: operator). The home-page seems to be devalued across a lot of terms (although not outright blocked or penalized).
Two possibilities:
(1) Your content is running up against some kind of adult content filter. I don't have much experience with that, but I suspect it's not the whole story here. Other content is ranking and I can get the home-page to rank on long-tail terms. Usually, Safe Search is all-or-none.
(2) You could be on the borderline of a targeted penalty -- either relating to that page or specific links and anchor text targeting that page. I'm not seeing clear evidence of that, though. You've got a chunk of links from directories, which aren't particularly high value, and that's about all I'm seeing. It may just be that the links you have aren't enough or seem to be low value, and Google's evaluation of that keeps bouncing around.
Minor thing to try, just in case you're on the border of some kind of spam threshold. Maybe tone down the double mention of "Sex Toy Party(ies)" in your Title Tag. It could be looking funny to spam and adult filters. Start with the brand name and something like "April Nites - Sex Toy Parties for Women". I'd drop "Adult", too -- I get your intent, but it just emphasizes the adult content nature more, and your home-page itself isn't problematic (I'd call it PG-13, honestly).
I'm seeing a little (minor) technical weirdness. You've got both "www" and non-www versions of pages indexed, along with a handful of sub-domains. Looks like your CMS may be creating some odd URLs, too. Not seeing anything excessive (i.e. thousands of URLs), but give that your site is small and has a relatively weak link profile, these things can add up.
Actually, you've got some really weird blog URLs indexed, like this:
http://www.aprilnites.com.au/blog/files/bb3a7ed4b561c6e8e2af28fb717a2edc-0.html
...along with a bunch of tags/categories. These odd pages are overwhelming actual, unique content. Try this command in Google to see more:
[https://www.google.com.au/search?q=aprilnites.com.au+inurl%3Ablog&gl=au]
Google is filtering out a ton of stuff, it seems. This doesn't directly explain the home-page problem but, again, it's weakening your other pages, potentially. Not sure what CMS you're running, but I haven't seen those odd URLs.