The triangle shape doesn't resonate with me; I think it's really awkward. I propose something like an 'imperial' profile yo-yo (called 'classic' in the image [1]), where the two disc-shaped halves can snap together.
[1] http://cdn3.volusion.com/cxlem.jbcmk/v/vspfiles/photos/YO_No...
I think that style of design is recognizable to be snapped together while maintaining separated shape that is not unwieldy to handle and pocket. Not to mention 'velo' sounds like a plausible rhyme for yo-yo and in my opinion, sort of onomatopoeically and etymologically conjures an image of a fast and nimble device like a yo-yo.