There's a twitch of a smile in Draco's smirk but it fades fairly quickly. Billy doesn't appear to have lost his cheek, but in that way he finds frustratingly tempting.

"I have several ideas, but to start with perhaps... " With a quickly whispered spell, Draco momentarily taps his wand to the tip of his tongue and feels the telltale tingle of magic, and a bit more when he licks his own lips.

When Draco shifts down to kiss him, he lets his tongue trace Billy's lips, creating a brief but intense stinging prickle of heat. It should hurt, if only for a few seconds, but the longer his tongue lingers the longer it will last.