You may want to take advantage of her slurping skills. Wink wink nudge nudge.

Warning: I can drive you crazy from even farther away. You might wonder how come your brother knows so much about her slurping. How are you doing now?

Is it weird that I find that sound kind of pleasant?

That was a sucker bet you should have seen coming from a mile away...

YDI for not believing him. You should know better by now.

Siblings, close friends, and others close to you know what buttons to push to get to you. That’s part of why it’s not wise to challenge them to upset you. It sounds like you might be a bit OCD if your girlfriend’s slurping suddenly bothers you. You are going to have to learn how to overlook minor annoyances in the people around you otherwise your life is going to be a pain.