The most common and most likely answer to this crossword clue is the 6 letter word HYADES
H
Y
A
D
E
S
More clues leading to the result HYADES
- The last place, perhaps, to introduce unknown stars
- Starry group appearing in Givenchy ad, essentially
- Group of stars with yen to hide in the underworld
- Appearing in biography, a desperate group of stars
- Greek god around young nymphs
- Those bringing rain in unknown quantity entering Hell
- Unknown in the Underworld, we’re always to be seen in the Bull
Buddy explains!

The straight part
We know that "we’re always to be seen in the Bull" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case we’re always to be seen in the bull = hyades.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.