How to get an online friend to start sleeping more?

Maybe ask one of my friends lol. I have a notorious habit of sleeping less than I should. Its really hard to convince them usually, especially if you are online friends

However if you stress enough of a concern or half-jokingly pester them when you are sure its "really too late" to be up still, it could work.

But dont just like... start a conversation to get them to go to sleep

Like have a conversation before hand then throw a "why are you still up :v :v Go to sleep"

Cos ask Zeppie. Shes gotten me to cama against my will a couple times like that

But be careful it might annoy him. But I would really address your concern and be really genuine about it

Well I've been on both sides of this and all I got say is just be genuine and nice to them like riku said even joke with them but still be firm that you're concerned and they should sleep.