Kieren hasn't, but he's already talked about that. He's wanted to, but being dead at eighteen throws a wrench into most of your plans, especially when you live in a small-minded town like Roarton. "What's this, then?" he asks, when he slides his fingers down Sirius' spine, taking his time to rub circles at the small of his back as he prepares himself for what he's about to do.

He's not disappointed when he slides those two fingers inside Sirius, that light press causing him to buck upwards with a loud shout.