If you're aiming to be a popular mainstream artist, don't even bother.
Assume any art you post online will connect back to you. Maybe it'll take a while, but if you somehow get popular, some obsessed fans of yours will find your shit. Some of them might be fans of your adult art before that.
Unless you know how to hide your style, but that'll be mega-hard. It's why I don't even bother posting the smut art I make, and just stick with commissioning from others.
If you really want to do it, hide your identity as much as you can. Don't have any links connecting you and your adult artist identity. And don't use the same profile/email you use for your adult art stuff for your everyday stuff.
Pixiv, Exhentai, baraag, rule34 paheal, and e621.net allow cake art; they're the most popular places i know atm. Inkbunny allows only furry cakes, but you can link to cake art from somewhere offsite. Imgur and Twitter don't allow it, but if you upload them as adult-only they 'might' not notice.
Also:
If you're peddling the 'real' kind of cake art, please save the prisons some trouble and just kill yourself.