We get tired of repeating ourselves to them... and they get tired of hearing us repeat it too. They get desensitized to it.
What I do sometimes is, I just validate my kids for their feelings. I tell them grown-ups get icky too. But we are a TEAM.
Or, I will actually just disengage... and then let them deflate by themselves, if there is no dire needs to intervene.
Or, I will actually tell my kids that MOMMY is going to nap TOO... and its quiet time. Then everything gets turned off, and its quiet time. I lay down on the sofa. But because I have a DAILY ROUTINE about it... my kids know that and like auto-pilot. So they do get in the groove of things.
It is the EVERYday routines, that you have for the child... and allowing them to wind-down too.... before a nap. When a kid is tired, also, they have a hard time listening... because they are tired or just too overly stimulated at that point and their threshold is full. Like an over flowing cup. But they have a hard time getting themselves keyed down... and focused. So, giving a head's up to them about what is coming next... "transitioning" them etc.
Or have an egg-timer on... and use that as a "cue" for your child.
Give him 1-2 "choices"..... then that's it.
Activities need a full-circle to it too... they start an activity, play in that... then there is a "finish" time and clean up. If there is a regular routine to that... then the child has a better way of cooperating. I always let my kids "finish" something first, before I stop them from it. Then they know when it is "done"... then it is nap time, or another thing to do.
Some kids just need more structure too sometimes... and it gets them in a pattern about it all. This is what schools/teachers do. So the child is more apt to then cooperate etc. At certain times is a certain activity... and end time, then nap time, then lunch, or what have you. Versus just having the child do it themselves.
My kids, know "my" routines... since it is a regular thing. And this helps them to then "know" what to do, what is coming next, what is their responsibility etc. Routines. That is real helpful. Patterning the child INTO the daily "schedule" of things.
Anyway, just some quick thoughts, It is never perfect, LOL!
All the best,
Susan