I usually inject a dub sack worth (two dimes or four nicks depending on how its bagged/quality) once during a day I use. I don't have much money atm, so I only have enough usually for one nice shot. I get a decent rush, pretty solid if I had a break and its good shit. It sadly doesn't get me to quite nodding. I probably need 3 dimes for a solid nod after a shot and a half back to back (can't let the first rush give me double vision or overwhelm me to much or I can't inject the other shot in good time, so gotta prep both shots and hit myself again right away). It's nice honestly when I have my junkie friend with me while I inject as I can hit myself easy on the first shot, then get him to hit me while I start sitting back for the rush.
I noticed injecting with friends can be a kinda intimate (in a non-sexual way) act. Even though I don't have the best relationship with the guy, we got to be better friends once I started shooting up and was having him essentially teach me how to inject. If it was a real close friend/one of my best or good friends, I could see the act being pretty special (kinda like having an ego death experience at the same time as a friend, or when I've introduced friends to DMT with my own extracted product). I have a fantasy actually of banging a girl I'm in love with then right after the orgasm, injecting each other for a IM shot of ketamine (+ meth and/or opioid) at the same time, giving each other a k-hole. What could be better, women, sex, and drugssss.