Freud has a name for that (your interpretation): **** fixation.

I think (I'm pretty sure) they mean a nasal spray. Nasal would be less descriptive, arguably: cocaine is also administered nasally, but not using a spray.

Edit:
How is that a swear word!? And rectum isn't!

You can't talk about psychosexual development on this forum. I think it's a conspiracy by the pharmaceutical companies.