Sebastian loves to hear him speak, whether he's mumbling his plans to himself, or cursing Sherlock, or just singing along to whatever is playing on the kitchen radio.
But the things Sebastian loves to hear most, is the poetry that fills Jim's head, the almost random, chaotic verses of varies poems and plays.
"Sin from my lips? O trespass sweetly urged! Give me my sin again..." He purred this line, hands against Sebastian's chest, and the assassin smirked, hands sliding down the side of a Westwear suit that would very soon be on the floor.
Sebastian smirked, running a thumb over the genius' lips. "You kiss by the book..." He rumbled, and let himself feel smug at the surprise in Jim's eyes.
Jim was not the only one to have watched the play, you know.