The first time i hit quad this happened to me.
I had pushed my pants down around my knees and sat on my couch.
All i remember is waking up,don't even know how long i was out and i couldn't find the syringe anywhere.
I pulled my pants up and started looking for it in a daze. It took me about 10-15 minutes to get my wits back enough to look in my pants.
I had dropped it in my pants and pulled them up without realizing it. I was flipping couch cushions over, squatting down looking under things with this 1 1/2 syringe in my pant leg the whole time and it never stuck me.
Last time i tried quads i could barely walk for about 9 days so needless to say I don't hit quads at all anymore. Just not an option for me.