Why do you want to die? If plunge it too fast you will. You might have some resistance to downers though.
l
Now if you want to get high:
Get that neede bleachy clean. Wash your hands and use rubbing alcohol on injection site.
a
When you think the needle is in the vein try to drw a little blood and plunge slowly because that shit will drop you to the floor.
a
To get it in the vein you got to be kind firm and not squeemish, also veins like to roll in certain areas.
y
You should proball just smoke it, but you might waste it. Even heroin is aleady kinda a waste.