A tribute is usually defined as "the money that is paid to a Pro-Domme as a fee for a session".

However, I've also seen it used in the plural - tributes - as a term defining the "gifts from a sub/slave to the mistress/domme."

Lately, I've been noticing things like:

Donate a tribute to Master/Mistresses (insert name) website -- wherein they are seeking a dollar donation to keep the site well funded

or

Here's a list of acceptable tributes & gifts:

The dollar tributes are clearly defined followed by a list of gifts. The gift list includes everything from clothing sizes, food and movie preferences to the make and model of a new car.

or

From various profiles of mistresses seeking subs:

"I want generous subs who are willing to give tributes to me, their mistress (insert name)..."

"I do require that ALL slaves pay a tribute each time they meet with me."

"...tribute will be expected once you've been found to be compatible."

This led to my original questions:

Mistresses / Dommes,

How do you define a tribute?

Have you ever asked for or required them from your sub/slaves?

Why or why not?