Finger sucking escapades?

The woman being the sucker and the man providing the finger(s), specifically. It had never occurred to me to try this but the idea popped into my head a few weeks ago and now it’s a major fantasy. I’m not totally sure how this is sexually stimulating, although I assume it’s something about being reminiscent of a blowjob. Any insights or experiences you can share would be great! I’m trying to figure out why this is so exciting for me, and how it’s potentially exciting for a guy.