A pair of socks.

You see a pair of Samantha's knee-high socks on the floor and you try to reach down to grab them but Erin struggles and almost pushes you off of her. You quickly pin her wrists and ask Samantha to grab the socks for you.

"What are you going to do?" the redhead asks.

You were planning to gag Erin with the socks but instead you plan on tying her wrists to the headboard. "I'm just going to restrain her," you reply as you struggle to tie Erin to the bed. She fights you but you are stronger than her so you eventually manage to bind her wrists securely.

"Let me go, you bastard!" the blonde complains, trying to free herself from your makeshift cuffs.

Then you hear a knock at the front door.

You still need to gag her to shut her up before neighbors call the cops.