I disagree with the other posters. I don't think pointing out the logical fallacy of calling you gay, and then touching your butt, will help at all.

They aren't logical to begin with. The artificial school societal food chain isn't logical.

For whatever reason, you're on the bottom (no pun intended) of the food chain in that period, and unfortunately, our schools are set up so that the bottom of the chain gets harassed constantly.

Telling them to stop certainly won't help.

Your choices:

1. Avoid them.
2. Tell on them.
3. Fight them.
4. Endure it.

If it's any consolation, the school society system is completely artificial, and means exactly nothing. Also, as bad as it seems now, it doesn't last that long. The thing to do is endure it the best you can without getting too emotionally scarred.

My advice would be to develop some inner confidence and peace. The tendency at your age is to blame yourself: "what about me makes them pick on me? Why do they call me gay? What can I do to make them stop?"

Those are the wrong questions. The problem lies with them, and with the system.

They pick on you because they think it makes them seem to be higher on the coolness food chain.

You are at the bottom, probably because you have been paying attention to other things besides the artificial school food chain (basically you pay attention to things a real human would pay attention to, but our schools aren't designed for that).

If somehow you could get some distance, understand the problem is with them and not you, and have some peace and confidence in yourself, it would help. First, you wouldn't mind the harassment so much, and second, they might let up a bit. Subconsciously, maybe they will sense your inner strength.

Also, find some friends. First period seems awful when there's no one to talk to in second period; not so bad when there's an understanding friend waiting...