That guy is obsessed with sex.
Someone who's shocked at everything all the time will seem like an idiot. At this point, putting your drinks in a glass shouldn't be surprising. I mean, come on. Only a fool lets himself be shocked by everything he sees.
Remember when you learned 呆ける? Well just cut the る part off the end and it's exactly the same! If you can remember that, you'll remember this reading as well.