When Louis saw Mason came in he shifted in his position checking if he has a wand in his pocket, thought he couldn't say that the other guy looked dangerous, but he didn't want to risk anything knowing he's a Death Eater, and he didn't believe any of them, so checking his wand was most natural possible reaction, but also it was ridiculous, especially considering that Louis invited the other guy here to hang out, and that Mason didn't have any reason to attack him.
"Hi mate." Louis nodded as Mason sit down, and waved the waitress calling her over here to take Mason's order. He already had a half-empty glass of beer in front of him, usually he avoided alcohol because of his job but since it was Friday's night, and he wasn't needed to be in his office until Monday at noon, Louis decided that he has enough time to become completely sober till then, it's not like he's gonna get drunk, after all.
Looking into the other guy Louis realized he had no idea what to say next. He curtail the need to apologize and disappear reminding himself why is he here, he needed to become part of the group, and the easiest way is to befriend one by one member. He gazed away and saw the picture of the broom on the wall. "I hate Quidditch." He blurted, what a awkward conversation this would be.