Uuuhhh i haven't read one with foursome, but there was a threesome i could remember which was Amorous Slave Girl. Though I haven't finished it yet at that time, so I'm not sure if there was a foursome or not in the latter chaps.
Well, if you can read MTL, I'm sure that you can find what you're finding yourself on the r-18 web novel sites; they all have NP and similar tag.
wow triple penetration , so wild i don’t remember if there triple but at least double Taking my elder brother as husband ( 2 ML ) *incest warning* Men at her feet ( 3 ML ) lady's petal are wet ( 3 ML ) ariel the lustful saint (2 ml) Their way of love ( 3 ml )