Tea the Handmaiden was one of the two handmaidens of Princess Macha during the Ancient Gathering. Described in far less detail by Sírlám the Scribe then her colleage Aífe the Banshee, it is assumed, that Tea usually held herself in the background, which is mostly consistent with what little we know know about her.
Tea was, besides Macha's handmaiden also her raicleach, a special position, which could be translated as 'cat', hence the cat ears and tails mostly seen on pictures of her. As raicleach it was Tea's position to serve her lady without stepping out of the shadows herself, rarely making an appearance, but being felt regardless. If the sign of the position indeed was a pair of cat ears and tails is, as researchers note, debatable, but cute nonetheless.