Does anyone know of any good Shojo manga that includes sex in it? Thanks so much!

I dunno any but if you choose shojo and smut or mature categories together, you should get a lot...
I've heard of this one though
http://www.mangago.zone/read-manga/erotic_fairy_tales_the_little_mermaid/

http://www.mangago.zone/read-manga/akkan_baby/
check out my shoujo smut list also:
http://www.mangago.zone/home/mangalist/6516/
number 5-32 only, the rest is without smut^^