Quote by Smoothtalkin_wolf
I am looking for more inventive ways then taking away the cell phone or grounding (if I could) a 18+ teen. He has been a total PIA and getting into trouble. Your thoughts?
Does he live with you?
If so, what rent/chores does he do?
Do you pay for his car/insurance? Clothes? Etc? Withdrawing funds is often a good way, especially the car, and removing certain parts of it so he can't drive it anyway.
Like Sprichler says, your house, your rules. I don't agree with violence except in self-defence. He is an adult now, and a spanking is not going to work. The last thing you need is a punch-up with your lad, in my opinion.
Why is he playing up? Are there problems in his life, or is he just being a selfish idiot? Sometimes an ultimatum (behave or get out) is the way to go. I presume you've tried asking him when you are both pretty calm what's going on for him? Is there somebody else neutral who could have a "chat" with him (like a family friend, etc)?
There isn't much you can do to control somebody that age, but you do have rights to be happy in your own home, and to evict him if he can't play ball. Children ought to respect their parents, and whilst it's awfully sad, the parents have a right to demand civility, just as the children do when they are of legal age. We all have a right to respect where we show we can earn it, in my opinion, and if somebody can't do that mutually with us, then we have a right to ask them to leave. Maybe putting something like that in front of him might help?
Good luck, lad!
More writing, less waffle... 
Meh face done!!
I can't do it now, I have a poorly back. 
