Rather awkward, sometimes somewhat painful sex. Adults like to make it seem like it happens less often than it really does... but in truth, lots of kids do it. It can be really fun if done with the right person for the right reason. REALLY fun. However, if attempted with the wrong person(s) or for the wrong reason... it is most likely to prove disappointing. In general, good training for the sex of later years.
My high school sex experiences were great because I was really in love with the person I did it with.
I only had sex in high school because it seemed like everyone else was, and it sucked.