Source Advice

Rather confused with how to tag a "source" for something like a paid reward from Patreon for example.

If I'm the one who has paid for the reward, thus allowing instant access via the Patreon user themselves how would I go with entering in a source since I don't need to reference websites like ex-hentai, and other (re)hosting websites?

If the image has a post, even if hidden to normal users, you can add the link as source and use the protected link tag. Otherwise you can just use the artist's patreon account as a general source.

The direct link as above, with the profile and period of reward referenced somewhere, if secondary sources are ever added then that period info should go there