DS1 is 3.5 and has always been very "active" as people used to say (meaning "he crawls/toddlers/runs non stop, poor you"). He is always everywhere, doesn't stay still, it's hard to keep him sitting in the doctor's room, for example. (He can concentrate when he is playing, sometimes he spends a good amount of time playing by himself so I'm not worried about attention span or concentration).
Every time we go out his hands are everywhere, fiddling with the windows of the trains, licking mirrors, playing with supermarket displays... The worst part in when we go to a public toilet and he touches the loo, the rubbish cans, the drain in the sink... Today he unscrewed some metallic thingy in the sink! The moment I get my eyes off him he does something.
I know curiosity and restlessness are to be expected in young children (and these are healthy traits!) but isn't he old enough to know better, at least in some situations? How do I make him slow down just a little bit?