....wow. Kids nowadays. That's ****** up. Tsk.

Must have had trouble falling asleep

I work in child care and policy and procedure for not only child care but also right up to the first years of primary school is that no child in any circumstance is to be put in a time out because it lowers their self-esteem, yes this can be extremely frustrating when the child has actually done something wrong but "masturbating" as you called it actually isn't wrong for this age group as they're exploring themselves. But in saying that it would be a good idea to monitor this behaviour because there could be an underlying reason as to why they're doing it

he must have finished off at home.. no point in punishing... wonder who he was thinking abt

Are you sure you're a licensed educator?? Way to mess up the kid. If it's a thoughtless fumbling you could have let it go. If it was going on for a long time, you could have told him nicely that those are his private parts and that he shouldn't play with them at school/in public.. No need to sexualize a young child. To him, it's just as normal as picking his nose, which shouldn't be done in public either.

Worst way to deal with it. You don't pubish a child for masturbating. Lol get it?

in preschool you should not punish him. if he truly knew what he was doing at his age that points towards sexual molestation. you need to talk to his parents

masturbation in preschool student is completely normal at that age children are experimenting with there body and there's no reason for putting him in time out

Well duh, why waste nap time, make him learn to do that during masturbation time.

Wow lol that sucks