Can be used in oh so many different ways; universally. History: Named by two kids Dan and Suzanne from Massachusetts. It was at first used normaly as in "Oh look at the baby over there, soooo tender and maternal."
A loud lesbian then expanded this word especially at a Summer college class in Maine. It is now used many different ways. Embellishing the word and over-using it is part of it's charm.
This word sprung the usage of "rare" or "prime" or "medium rare."
Dude, that chick is oh so Tendah (Tender)." "This meat is wicked tender.