What does the top of a woman's butt crack actually smell like?

Recently, during foreplay, my husband has started smelling the upper part of my butt crack, near the top of my thong. When I ask what he’s doing, he says he’s smelling my pussy. I’m like, "Um, that’s not my pussy."

But does it smell like pussy? What does a woman’s upper butt crack smell like? Is he trying to work his way up to licking my ass?

I’ve never been self-conscious about letting him go down on me because I’ve tasted myself and I think I taste good. But I literally can't sniff my own ass, so this freaks me out a little.

Important side note, because I'm sure someone will ask: I don't think this is part of a long-term plan to convince me to have anal sex. He’s much less interested in anal than I am because he’s worried about poop. It's funny because in regular life, I am very grossed out by poop and he's not all that squeamish about it (he handled most of the poopy diapers when our kid was little). But somehow, when it comes to sex, that's reversed.