this is a kink post. if you aren't into the kink, there are many better things you can do with your time than comment on it.
the thing that tends to separate ace people from allo people is a lack of innate sexual desire. a lack of NEED to feel that, a lack of that tugging in your gut, the pulling, the desperation that comes naturally...
But ace people, just like anyone else, can enjoy activities, and want to do those activities. crave those activities. Games that they enjoy, books they want to read, songs that urge them to sing....
When you do activities you like, you develop habits and wants, cravings to do those things again, especially when you might be feeling down, you need a pickmeup
And -- ace people do still feel physical pleasure. It's different, their minds don't react the same way, but their bodies still trigger rushes of endorphins, their bodies still feel these physical things.
So what better way to break a cute asexual than to gently, gently, ease them into realizing that you are good at making them feel good. They may not crave sex, but you can condition them over time to crave having a good time with you.
Condition their mind to crave enjoying yourselves together because it's a fun activity. Create, bit by bit, a sex drive by engineering it out of normal wants and needs and desires.
Until your cute asexual is messaging you at 2 in the morning asking you if you're free. They may not have the exact same kind of sex drive you have, wanting sex -- but they want sex with you. Because you showed them that they like it.