Morning wood...again

I awoke the next morning to feel something large and hard rubbing against my ass. I lay their for a moment trying to remember how Susan and I had ended things last night, and this most definitely was not it.

"Good morning," Mike's familiar voice said from behind me, and a large muscular arm wrapped itself around me.

"Thats not who I went to sleep with," I said, surprised to hear my own voice instead of the intern.

"I know, but you did make me a promise last night," Susan said.

I thought for a moment and could vaguely remember in a horny frenzy agreeing to something. Then it hit me. I had promised that if she went down on her little intern friend, I'd let her have gay sex with me. With Mike's big black cock pressed against my ass, it suddenly didn't seem like a good idea.

"Can you use someone else?" I asked.

"Oh come on, you guys have been best friends your whole life," she said. "I guarantee you that at some point, maybe in a drunken horny fit, one of you has jerked off while thinking about then other one. Why don't we let it play out?"

I was panicked. I didn't know what to say.