I think it's good to play with your fingers just slightly over the neck, that way the strings vibrate more evenly, and tapping is made way easier. For examle, I was trying to show my guitarist the intro riff for Sweet Child Of Mine, and since he learns by ear, i tapped it out(for lack of the higer B and e strings) at the top of the fretboard while fingering where needed. And it's really hard for me to do that with my bass down by my waist.