Go with her

"Yeah I am actually", you lie but she believes you easily enough. You weren't invited to frat parties very often and had no idea this one was even happening but, it's not like they maintain high security or anything, you can just slide in with Kim.

"Great!" Kim says, grabs your hand and leads you ahead.

Soon enough you arrive at a three-story house. Music is blaring, the lawn is cluttered with plastic chairs, disposable BBQs and other picnic paraphernalia. Obviously someone has been enjoying the sunny day. As the two of you make your way inside, you observe the people - it's mostly just like you remember, with certain differences:

All the women are wearing high heels and stockings, but they are certainly not uniform in their appearance. All the colors of the rainbow are represented, as well as a multitude of fashions. After a while you realize that there are several, roughly similarly dressed groups. First group is formed by girls in skintight minidresses and towering stiletto heels, second has girls in cheerleader skirts and wedge heels, third one consists of short-shorts wearers in platform sandals, and the members of the fourth is made up of the women who do not fit in the other groups. Delightfully, each and every one is wearing stockings, though the colors and styles vary wildly. Pretty soon you're walking around with a permanent stiffy in your jeans, to the mirth of the people present. You realize that, despite the abundance of female skin visible, the other guys present do not act any different from "normal" and they certainly don't sport visible erections.

Which makes sense, since you're the only one to whom all this is new and exciting.

Sitting down seems like the best course of action, so you do so after a couple foolishly vacates a couch in the main room. Kim departs elsewhere, claiming she wants to find some friends of hers.

Well, there are easily over a hundred people milling in, out and about. You could pick a girl from any other group to handle your problem or multiple girls - or follow things as the party is getting rowdier and rowdier.