Cumming in ass crack

When my current gf and I first started going out, for a while she wouldn't let me actually put it in her pussy (Asian girl more conservative), so she had me put my dick between her ass cheeks. I'd rub up and down, and she'd squeeze her cheeks together so I could get off.

Now we fuck regularly and in more “standard” way, But sometimes, when I'm about to cum (especially when we are in doggy), I like to pull out of her pussy, and then bury my dick in her ass crack and cum

She says it's gross, and sometimes she can feel the cum going into her asshole. But actually, she was the one who inspired this kink in me in the first place, and sometimes I feel like fucking her ass crack is even better than fucking her pussy.