IIS forwarding from one computer to SQL Server on another computer

I’m a newbie in the system administration. There are tons of tutorials how to make port forwarding using your home router. So I can easily make SQL Server, installed to my computer, available outside by forwarding everything that comes to the router port 1433. Router:port 1433 –> Computer with SQL Server

But how to do that if I do not have a router (or access to it)?

I have an Azure VM with IIS (I host a website there). I have another Azure VM with SQL Server on it (this another VM is on the LAN with my VM with IIS. I do not have access to the VM that makes the routing for this LAN.

So my task is to make SQL Server available via internet to specified IP address using IIS.

There are tons of videos how to make url forwarding for IIS and no articles or videos for PORT FORWARDING.

Task: I have an address (blabla.dididi.com). I want to call it on port 1433 and get access to SQL Server installed to the computer on the same LAN. IIS:port 1433==>SQL Server on another VM

Could you please give me a link to the article or video with detailed instructions on how to do that? Or write the answer with detailed instructions. Thanks.