Playing the cello is done while seated with the instrument supported on the floor by the endpin. The right hand bows (or sometimes plucks) the strings to sound the notes. The left-hand fingertips stop the strings along their length, determining the pitch of each fingered note. Stopping the string closer to the bridge results in a higher-pitched sound because the vibrating string length has been shortened. On the contrary, a string stopped closer to the tuning pegs produces a lower sound. In the neck positions (which use just less than half of the fingerboard, nearest the top of the instrument), the thumb rests on the back of the neck; in thumb position (a general name for notes on the remainder of the fingerboard) the thumb usually rests alongside the fingers on the string. Then, the side of the thumb is used to play notes. The fingers are normally held curved with each knuckle bent, with the fingertips in contact with the string. If a finger is required on two (or more) strings at once to play perfect fifths (in double stops or chords), it is used flat. The contact point can move slightly away from the nail to the finger’s pad in slower or more expressive playing, allowing a fuller vibrato.