Hold out and get a nice reward.

You focus on anything else going on in order to hold on. You manage to make it through her orgasm without cumming.

"I was kind of hoping you'd cum in there," Ellen says.
"You sure as hell tried to make me."
"A stud like that needs to be rewarded," Amy adds.
"I know what you want, you little slut. Considering how good he is, I just might let him do it."
"Should I ask what you're talking about?"
"Nah. Here's what you need to do though," Ellen replies.

You pull your cock out of Ellen's asshole- a slight pop occurring when you do- and aim for a new target- Amy's ass.

The redhead leans forward a bit more, her lips meeting Ellen's. You slowly enter her not-so-virgin ass. She is a bit looser than Ellen's. You imagine that there are stories of her using toys in there to explain this.

"I know that this isn't the first time you've taken 2 dicks at once," you say, "How about with Ellen?"
"We both got DPed by those Nerds," Ellen answers, "We took them side-by-side, right Ames?"
"Oh yeah. They were soooo rough with us."
"That's not what I meant though. I meant, have you taken a DP like this with Ellen involved this intimately before," you explain.
"Ohhhhh....no, actually. This is...my first time," Amy says, adding some false innocence to her voice at the end.
"You're such a slut and I love it," Ellen says, kissing her again.

The two of you fuck Amy in unison. The redhead cums at least three times. She cums so much and so long that is a little hard to tell where some orgasms ended and others began.

"You've got to be close," Ellen says, "You can cum inside her if you want...or you can make her suck you off again. Either way, I have another naughty tale to tell you."