Ianto was dizzy enough as he finished the first one, listening a bit and then smiling. "You keep an eye on most people though," he pointed out. "I'll have to do something to keep your attention this time. Though I can't imagine what."
He was getting pretty tipsy pretty quickly. It might have been embarrassing... if he cared at all with the alcohol coursing through his system.
He got to the end of his first and reason told him to stop there, but he refused to be such a lightweight that he only had one. He slid the glass over for a refill.