For your bass playing pleasure here is the G Major scale on bass played in a high octave. The root notes (G notes) are shown by the diamond shapes. All the rest of the notes are the scale notes.
This scale begins on the 10th fret of the A-string. The easiest way to learn this scale is to play through it as shown. Afterwards you can learn the note names. It's pretty rare for a bass player to play up that high for a whole lot in a song - although it does happen, and by some quite good players from genres as different as jazz, funk and progressive rock.
A few ideas on incorporating this scale into your playing is to play a good bassline way down low, but tastefully throw in one or two of the notes here and there, perhaps as lead in notes to a chord change or new bar. Another standard of playing is to slide up to, or out of, one of the suitable notes from this scale to add emphasis to your bass playing.
You can get creative. For instance if you're playing a low bass groove on G-note you might be tempted to slide into or out of one of the high G notes. Yeah, that sounds good. But, B and D will work fine behind your G chord too! Build your music theory knowledge and ear and you'll come up with some great stuff.