That’s an interesting complaint. Many sexually active men and women with ADD/ADHD find their sexual experiences are improved when they ‘time’ them to be occurring while their meds are active in their systems! They describe being more focused on the event(s) occurring, more attentive to their partner, and their partner notices a greater intimacy (connection’), etc.
These meds are known to have an opposite side effect called priapism, an erection that lasts tooooo long and can be dangerous if not treated if the erection lasts more than 4 hours!! (While many men can only dream of having this experience, many women are more than thankful that it does not happen!)
As your son proceeds toward independent driving, it is highly likely he will want to drive on weekends. (Different States have different restrictions with regard to hours of the day, or number of passengers, age of passengers, etc., until they’re 18.) Even beyond these restraints, it is important you consider the importance of him being ON his medication when driving, which will impact whether or not he can drive on those weekend days.
Statistics are clear (AAA and other sources) that new drivers between 16-25 have the greatest amount of automobile accidents (per driver), AND that within that age range of new drivers, those with ADD/ADHD who are unmedicated have 25-30% MORE automobile accidents than the other new drivers in that new driver age group!!! Aside from the obvious increase of physical injuries and deaths as a result of the increase in at-fault accidents, don’t forget what will happen to your (his) insurance premiums!!
It may be important to not ignore that the time will be soon upon you, and him, where he may need to ‘choose’ between driving on weekends or masturbating on weekends ;—)
Another possibility could be that, as someone with ADD/ADHD, he may have some impulsivity, needing immediate gratification and no patience to wait, whether it’s waiting in line for something, waiting for a light to change, waiting for a class to end, or waiting for the ejaculation to occur, having not had the experiences of longer periods of foreplay/arousal as being ‘normal’ and impulsively expecting more immediate culmination of the act, therefore concluding that a delay from what he is used to is a problem, rather than just ‘different,’ and if accepted rather than distracted by it, it would not be a distraction to the focus of achieving orgasm.
No mention was made as to whether he had tried other ADD medications, like Mydayis, or Vyvanse or Adderall XR, (with/without Adderall immediate release). The side effects may be different enough and the benefits as good or better.