Snape sunk the sound into its new home. Just a fractional pressure was needed, the size was accommodated without problem but the slow progress allowed the protrusions to scratch the inner lining of the piss passage forcing the itching potion to marinate as he slowly pushed the implement towards its new home, prodding the device upward with open handed slaps. Hermione gasping breath deepened as each nudge on the sound reverberated through her hole, as the infernal device was seated completely. For one fractional breath, Hermione interrogated her discomfort; not painful; just a ache, she longed for her hands to explore but thankfully the bondage prevented her from scratching that proverbial itch, instead she understood it is about to get worse, as Snape points his wand to the bottom of the sound, giving it a tap to allow the grappling hook function to deploy, spearing outwards to curl outward into inner flesh, harpooning the torture device in-place, preventing the length of metal from being removed without complex magic. The previous blunt ridges adorning the length of the metal were suddenly sharper, affixing themselves to the intimate lining plugging her fully, heightening the itching sensation as the combination of itching potion and sharpness burnt her skin. Snape continued unabated as he squirted the remnants of the itching potion through the now hollow tube, before he connected the abused orifice to piping that would feed the discharge reservoir.