ear nuts need tightening?

Sorry that sounds almost indecent !  An ear nut is the small part, or finding, that is used to hold a post or stud against the ear.  The ear nut that you can tighten to avoid earring loss, a side view of it, looks like two curls touching in the middle.  The middle is where the post comes through and the two curls press against it will some pressure.  After being applied and removed many times ear nuts can become loosened.  All that is needed is to place an index finger and a thumb against both curls and press them towards each other. Make sure the post is not in place when you do this.  Then try to place on the post. It should be more snug than before tightening.