shag bands are jelly bracelets of which lots of people wear, mostly emo or scene. there are hundreds of different meanings for them but the ones i know are:
black: all the way
green: outdoor sex
clear: whatever the snapper wants
orange: kiss (peck)
purple: full-on snog
pink: lovebite / hickey
glow in the dark: using sex toys
gold: all of the above
he snapped one of my black shag bands, damit! now i have to f**k him!
i have to give him oral, because he snapped my blue shag band.
hahaha, she snapped my green shag band so now we've arranged to do it outdoors :D