You, your girlfriend, and your twin sister are all hanging out. You're having a good time and your gf and sister get along well! However, your gf doesn't know that you and your twin have been fucking for awhile now! While you're all together, your twin secretly teases you, flirts with you, and makes a lot of sexual innuendos, right in front of your gf! Your gf gets a text calling her intimate work and that means you and your twin sister are going to be alone together for awhile. The second she leaves your twin is feral for your cock, so turned on by the two of you lying to your gf's face! Like the unhinged, insane slut that she is your twin begins sucking your cock, worshipping it with her mouth. She's talking so dirty to you and reminding you how much better she is than your gf. Finally she begins riding you, using every inch of your cock to get the two of you off together before your gf returns home! You don't want to get caught do you? It'll keep being our secret!