I'm pretty sure "oshiri cantabile" is a masturbation toy, like a fleshlight, except it's made to mimic an anus instead of a vagina.
To use the oshiri-cantabile, prepare the wank material, apply lots of lotion, then use!
couldn't think of non-awkward wording; so left following words as is:(oshiri=butt, rear, ass, etc)(okazu=side-dish, fap-material, masterbation-aides, etc)come, come everyone...
The oshiri-cantabile resale is starting.