A bunch of my friends and I all went to one friend's house to watch a movie and hang out. When my girlfriend arrived, I thought it was odd because she was wearing a skirt, something she usually doesn’t do, especially at these informal hang-outs. But I didn't put too much thought into it. We all went downstairs and settled in to watch the movie, the couples pairing up of course. My girlfriend and I snuggled up under a blanket on one of the sofas. About halfway through the movie, my girlfriend looks at me and playfully grabs my sweatshirt string in her teeth. I catch her meaning, and we start making out while playing tug-of-war with our teeth. It was one of the hottest make-out sessions I've had, and I guess I got a little excited. She noticed, and before I knew, she had slid her hand down my pants. After a little playing, she actually unzipped my pants and directed me right up her skirt! The sex was incredible, especially because we couldn't move too much or our friends would find out what we were up to. She actually had to bite my hand to stop from moaning out loud. After the movie, we went back to my place, and no one would have guessed that we had incredible sex right there in the room with the rest of them!