A quality orgasm that includes giggling to replace the customary screaming or moaning, which is pleasant and does not annoy the neighbors.
My GF is a ninja with sex; she's about to cum, so I brace for hurricane-force screams, but she pulls a gigglegasm instead. So cute when her boobs bounce along with it.
Gigglegrass is a substance which, when smoked, will induce a general sense of happiness, frivolity and merriment. Giggling is a side-effect of this mood. While normally reserved for the upper echelons of grass quality,
Girl A: What are those silly boys up to?
Girl B: Oh, well you know, someone's been into the gigglegrass a bit!
Girl A: Oh, susan!
The climax which is sometimes achieved during giggle sex. This consists of an extended period of uncontrolled giggling. The female often fakes the gigglegasm in an attemp to end the current giggle sex session.