Warning: Parental Advice Coming..

So, we have a son that is just about to turn 18. And I, like many parents I know, will likely NEVER outgrow the urge to give advice. With elder teen and certainly adult children, a helpful approach (which still allows the parent to still give advice when it cannot be contained) is to acknowledge (in good humor) that the receiving party will probably not want to hear any of this. Something like:
“Warning label – parental advice coming, listen at your own risk..”
Or
“CAUTION: Unsolicited parental advice erupting..”
This is even more effective when it is in the written form (email, etc.) which gives the receiver space to further brace himself for something that has more to do with the parent’s than the (grown) child’s need.