On the tip of the tong

Source: www.sozoexchange.com

This is a phrase which means to have something that is on the verge of being remembered.

This expression comes from the idea that the thing is just about to be said but can’t quite make it out of the mouth.

The phrase also means barely inaccessible.

For example, you can say, “I can almost remember her name; it’s on the tip of my tongue.”