Depending on the circumstances, yes, that would totally be illegal.

It’s called “aiding and abetting”. In most countries it’s illegal to convince someone to do something illegal.

If you are someone the victim sees as an authority figure (especially if the victim is a minor), a bunch of other other charges can be added too.

In Canada, the UK or the USA, for example, someone who “aided or abetted” someone to commit a crime can be punished exactly as if they had committed the crime themselves.