ask him to be gentle

It doesn't seem like he has any intention of stopping at this point, and you have heard that anal sex can either be terrible or great for a man depending on the way the man doing the fucking treats the ass of the man getting fucked.

"Please be gentle. I'm a virgin"

You're not sure where that came from. I mean, you aren't a virgin. You have had sex with plenty of women, but for whatever reason that just seemed like the easiest way to get your point across.

"Oh, I will make sure you love getting fucked when I am done with you."

With that he helps you to your feet and leads you over to the bench right in front of his locker and tells you to sit down for a second. He lets go of you and reaches into his locker. You can't tell what he is reaching for, but if you're fast enough you might be able to get away from him and maybe reason with him while you're not pinned down to the ground with his cock pressing up against your ass...