>>104569446Confession.
I use my imagination and I base myself on other doujin artists I like. The rest is just basic art studies on how skin and muscle works. Sometimes I also use 3d dolls to help on some proportions too.
Now, I don't doubt there's sick fucks out there using actual cp as reference and I hope they get caugh someday, but really besides the cripling morality issues and guilt there's no science about drawing accurate kids.