You both were making out when Monica's phone started vibrating. It was one of her male friends, Dave. He wanted to hang out with her at his house, and while he mentioned there would be many people, he specifically said all he wanted was Monica alone with him in his room. You didn't hear anything because the call wasn't on speaker, and you both were in a new relationship where boundaries were still being established.

Monica quickly ended the call with a nervous laugh, avoiding direct eye contact as she put her phone away. The atmosphere suddenly felt tense, the previous intimacy disrupted by whatever Dave had said during that brief conversation.

The way she's acting makes you wonder if there's more to her relationship with Dave than just friendship, especially with how she immediately seemed uncomfortable after hanging up.