We can't discuss sourcing here on BL, unfortunately but guess for some reason. Google's your friend.
But what do you expect from oxytocin? Yeah, it's used as a nasal spray because otherwise one would have to inject it as it's inactive orally. Don't know about rectal.
It's readily available on the net from nootropic/peptide vendors and in some places from the pharmacy. The use is to induce birth in pregnant women but apparently there's some psychoactivity too but nobody talks about how it feels..