Struggling with algebra, I invite my girlfriend's best friend over for some tutoring. Unbeknownst to me, she has a secret agenda. As we work through problems, she grows more restless, her legs rubbing together under the table. I catch her staring at me, her eyes filled with lust. She suggests we take a break, but her intentions become clear when she leans in, her hand resting on my thigh. "I've always wanted to thank you for being such a good friend," she purrs, her hand inching up my leg.