What should i do??/ 20charactersssss?

im 15 and my girlfriend is 15 and she was sleeping over. we were home alone for the day and we were watching a movie. we were all snuggling and cuddling then we started kissing and making out. during that i got sooo hard and horny. she sat on me and felt the bulge in my pants. i was a lil embared, but then she smiled and grabbed my crotch. what does this mean??