Wording for Adding mortgagee clause

I was at a RE seminar a few years back and one of the speakers suggested when selling a home, to place a 2nd lien on the property for a minimal amount say $500 or $1000, to be paid when buyer sells the property. The reason for this 2nd, was that if the buyer were to default on the first, you’d be notified immediately. I thought this was a brilliant idea. Has anyone tried it? Does anyone have any sample wording that they use?

Did this guru tell you how to LEGALLY record against a property that you have no right title or interest in ?