You live under your parents roof, probably because you have no where else to go or can't afford your own place, which in itself is fine. You are 22, they can easily kick you out, your like 4 years past 18. You have never done an "illegal drug" before? What do you think the juice is? I'm sure you don't have a prescription. So, your parents don't want illegal drugs in their house and probably don't want syringes in their place either, I totally am on their side as far as not wanting contraband in their house. Your lucky they don't get pissed and call the cops to teach you a lesson if you continue to go behind their back about this.