I consider 2nd day hair basically get up and go hair, with less than 5 minutes of work on it.
I have medium to coarse hair (definitely leaning toward coarse) that is low porosity (for the most part), and really dense.
I have never gotten "true" second-day hair IMO. Pony-tail hair/half-up half down worthy hair, yeah, but not truly "down" unless I spend about 15 minutes with water/conditioner. I think it's because my hair is at that short-ish length where a pineapple is not that effective, but it gets really smushed by the satin sleeping cap.
I have I guess what you'd call "natural layers." They just grow like that... in various patterns and strand widths. I have a coarse layer, finer layer, medium layer, ringlets, wave-ish things, random straight pieces, random kinks...
Hair Type: 3c, Med-High Density, Low Porosity
CG since '09
Low Poo: KC Come Clean
Condish: AOHR, TN (Avocado), TJ Balancing Moisture
Leave in: GDL, KBB
Curl Lotion/Gel: CHS/CK
Others: CJ Curl Rehab, Jojoba Oil