I encourage you to please tread carefully when trying to promote yourself on Reddit. Reddit is full of users who specifically use the website for free porn, and generally, posts titled "hey come buy my vids" (or similarly) do NOT get the greatest responses. They take their "Reddiquette" pretty seriously. In fact, Reddit users are ruthless and will find a way to get under your skin, even for the tiniest of things.
IF you choose to post on Reddit, pleast stick to subs that you "fit" into. Don't just spam any and every NSFW sub. I've been seeing the same girl spamming my beloved r/bigtiddygothgf for the last month with non-gothy boobies and it's just breaking my heart. And I definitely suggest NOT giving your posts any "advertisement" treatment.
I would stick to the list that
@Songbird_Shelly includes. Those all seem pretty tried and true.