A positive exclamation that can be used in many contexts. 'Worm' is a common response to good news, new information or to show enthusiasm. In other words, it is a postmodern substitute for 'slay'. The phrase was coined by a prominent Californian dyke and can often be heard being screamed by gays in East London.
'That outfit is worm-ilicious'
'I just got a new carabiner'
'WORM!!!'