You take her ass.

To make sure things go smoothly, you take some lube from a nearby shelf and put a bit extra on your dick.
Bumblebee's sucking was good, but no need to risk things.

You move in closer and line up your dick with the Heroine's only available hole- her asshole.

You enter her slowly, letting her react to your entry.

It startles her, causing a little exclamation into Starfire's pussy and a quick, accidental thrust up into Raven's.

"He'll take it nice and slow," Raven says.
"You know you wanted it," Starfire adds, playing with her tits some more.

You get no resistance as you push your way further in, the Heroine relaxing and accommodating your entry into her (once) forbidden hole.
She is tight, but enjoyable.

Raven uses her Kegel exercises to squeeze down off and on with the strap-on cock, which, thanks to magic, feels like a real dick for Bumblebee.

Raven cums.
Starfire cums.
Bumblebee is there...but resists.

Raven gestures to Starfire, who uncovers Bumblebee's face for a minute to speak with her.

"You can cum like normal with this on," she explains, "When you want the cock to cum, just think hard about it and...well, enjoy."
She nods...and cums, soaking both you and Raven a bit.

You keep fucking her throughout this and the orgasms continue.

After about 10 minutes, you are at your breaking point.
Raven has cum 4 times.
Starfire has cum 5 times.
Bumblebee has cum 7(!) times.

"Where do you want me to cum," you ask the room.