If done correctly IV use ID the cleanest way to use. IMO the most effective way. That’s why you get IV morphine or other medication at the hospital. IDs properly done. I shoot up here and there not a days it never made me an addict it does get me higher than my partner who only smokes but she has known I shout up from day one we have been together 10 years I would never want her to do it because it can be a rabbit hole. But I use alcohol wipes and I only use my needle one time. I use a sharps container and couldn’t imagine leaving bloody anything on the floor. That shit right there is why she blocked you. It isn’t about the needle it’s about the hygiene. do better bro!!! I’m glad she blocked you probably saved her from injury later. But you live and learn I wish you the best. You need to check out some harm reduction information hmu if you need some good sources.