Used to describe things or people that are annoyingly sweet and happy.
My thoughts about work are decidedly not happy-angel-glitter thoughts.
She's so cheerful, when she farts happy-angel-glitter falls out.
When you thump someone on the head for saying or doing something utterly stupid.
Vicki at Glitter Frog gave a web site a "head-thump" for advertising math tutoring but using bad grammar.