Swallow

You cum hard in her mouth. Initially she makes a horrible face, but you change her taste buds so she loves the taste of cum more than any other flavor in the world.

Denise's face quickly changes to surprised pleasure as she tastes your next load. You love the look so much you wish you'd keep coming. Spurt after spurt comes out and Denise greedily sucks them down. The girl fingering her pussy picks up her pace, causing Denise to squirm in pleasure.

Finally Denise tenses up in a huge orgasm. You make yourself stop cumming and pull out of her mouth. Then you smile and make a few more changes to Denise.

"Did you like that orgasm?" you ask. "From now on you'll have one whenever a guy cums in your mouth. Also, for the next year you need to give a BJ to a different guy every day."

"What?" says Denise, "I'm not doing that!"

You laugh. "You won't be able to resist. You'll start going through withdrawal without your daily cock. But look on the bright side. With all that practice, you'll definitely be the best!"