When you are gettin a chick from behind who has long hair, grab the hair and thoroughly wipe off your dick after you've finished. Keep in mind guest towels are for decoration only so if you use it, dont expect another invite.
Your Roommate: Hey, whatever happened with that chick you brought home the other night?
You: Oh, she wont be back, I used the guest towel.
Someone who you dont want to show up but they do anyway. You probably dont like him/her because they are annoying, though you always see them. Otherwise known as the buzzkill of the party.
1: Who all showed up at the party?
2: Just some of the guys...oh and my guest-friend, Terry