It was a perfectly good way of describing him, as far as Sam was concerned. Cas had asked him why he'd ever want to give anyone that much power over him, but the answer was that when it wasn't about power, it felt good. It felt like belonging. So he accepted the possessive title of being Veronica's Sam, and smiled.
"Hi, Lilly," he said, a little bit of amusement creeping into his tone. Her reaction wasn't unexpected, but he was modest enough not to react except to avoid the urge to chuckle. It was harmless, and if it provided a little bit of levity to the situation for Veronica, he wasn't going to complain about being objectified. Though based on what she'd just said, he had a feeling it might frustrate Veronica if that was the only thing Lilly took away from understanding their relationship. "It's nice to meet you, again."
He lowered the hand holding Veronica's to his side, but didn't let it go. "I hope you don't mind me being here while you catch up." He was tempted to add the same caveat-- that he'd wait outside if they wanted a moment alone-- but ultimately he was going to listen to Veronica on that one. He figured that if Lilly seemed uncomfortable with having him there, she would ask him to go for her friend's sake.