Suggested video functionality is controlled by YouTube.
There is, however, a workaround that you can implement to prevent additional videos being suggested and displayed to your students.
If the URL to your youtube video contains a "?" character, then you will need to add this to the end of the URL &rel=0
So for example the URL from the address bar in a browser:
If the URL doesn't contain a "?" you'll need to add the question mark as as well. ?rel=0
So this URL:
If you have any questions, or require further assistance, please click here to create a support ticket.