Its the same basic principle pal.
You're whacking something intended for oral consumption into your circulatory system...
I think it's the sugar and stuff that's the most damaging.
As damaging as meth maybe? I guess not. But still...pretty dangerous and the fact that its really not much (if any) stronger than just drinking it... Its pretty much self harm.
At least when you iv meth you only need a tiny ass fraction of the dose youd need if you took it orally.
And to your warm buzz question id start with drinking 50mg worth on an empty stomach and add 50mg more every 15-30 mins until you feel nice! Oral morphine can make you feel/be pretty sick in my experience lol
Once you feel the nod coming on put the damn bottle down before you OD or even worse SPILL THE DRUGS