Since this is your first time sucking cock, and you claim to be straight, we have provided you with the mouth guard. It will help you keep your teeth out of the way and allow the men using you total access.  

Now all you need to do keep your tongue moving back and forth on their shafts and swallow their loads.  

There are over thirty guys in the next room waiting in line to empty their balls down your throat. Perhaps after the first twelve or fifteen men use your mouth, you will have had enough practice to remove the mouth guard. You are going to want to do a good job, since several of your friends are in line.