Ianto has decided that
drinking with a man whose IQ cannot be more than that of a three-year-old was not one of the most clever ideas he's had. Oh no.
He's a little intoxicated, but he might not look it at first glance. In fact, he appears to be trying to nurse it all away with the coffee that is often too strong for his tastes and some particularly gruesome files from work.
Yeah, he's never doing that again.
Bother him, really, you might learn a few things.