I snort both regularly. I also often consume small amounts orally, sometimes raw, sometimes cooked, also involuntarily. Both of these methods usually produce sneezing and/or gagging in me.
My injection site, the odd time for that method, is the soles of my feet. This is also involuntary and can be painful. Only dog hair seems to be injected and the problem is they stay in my foot. One recently went in very deep, got infected, swelled up and hurt. It was in there moths before I got it out again and boy, do they hurt when being pulled out. They have little scales on them and pulling them out is against the grain.
I suppose if I rolled my own they'd get in there too, but I haven't done that since university.