He makes an amused noise, biting back a comment about how last time Jack had control over Spike's body it didn't end so well and he should probably stay clear of any copycat behaviour, just to be safe. No sense in dragging up that old thing, though.
"Y'know... you don't have to be romantic. From what I can tell, that's definitely not what he sees in you in the first place." Okay, he can't help himself, but at least it's a gentle dig.
"That said, I bet it wouldn't hurt if you made an effort from time to time. Surprise him with something he'll like. Sometimes, you could even go for something that isn't your cock."