The candy store is also a brothel, so the 'candy' part is more just a front. So it makes more sense in that context.
You can get into the back room of the brothel by following some clues but it doesn't actually show up in the journal as tracked progress and I don't think you can actually do anything in the back room once you get there.
I played through this whole game again yesterday, catching up on stuff I forgot and seeing a few things that had been added since I last did a full playthrough, and man it's actually a pretty quality experience.
There are some things that I'd change, but overall just an extremely rad experience. The sex scenes that ARE there are hot as fuck too and make me excited to get to the really steamy shit with all these characters who are basically only introduced so far.